1 Introduction

The first ever historical material about skin and its diseases are revealed in the Ṛgveda. The mention of skin diseases in the Ṛks 1–117–7, 1–117–19 and that of the hair in Ṛks 1–126–7 and some liturgies related to them in 8–80: 5 & 6 are worth mentioning. The humans have been battling microorganisms since before our species had even evolved into its modern form. The Atharvaveda (AV) is a curious compendium of medicine in its various stages of evolution and contains the most primitive as well as some of the most highly developed stages of therapy. In the AV, the word ‘brahma’ is used in the sense of physician, whereas the word ‘bhiṣak’ is used in the Yajurveda and ‘rudra’ is used in the sense of primordial physician. Among the four vedas, the Atharvaveda deals more with various diseases prevalent during that period. Most of the vedic healing verses/liturgies occur in the Atharvaveda. The bhaiṣajya sūktas (hymns on medicine) which deal with diseases, their causes and cures, show a remarkable insight into the subject of health sciences. That is the reason that the Atharvaveda is considered to be the precursor of Ayurveda or the science of health and longevity. The Ayurveda is listed as an upaveda or subsidiary of the Atharvaveda (Modak, 1993; Wise, 1986; Dominik, 2003; Khare & Katiyar, 2012). These sūktas contain many prayers for health and longevity. Several diseases like fever, leucoderma, leprosy, jaundice, diabetes, dropsy, skin disorders, troubles of the ear, nose and throat, fracture of bones, diseases of the heart and tuberculosis, are mentioned along with their treatments in the Atharvaveda and in the later Ayurvedic texts (Karambelkar, 1961). These diseases are caused by germs, violation of the laws of nature, anger of deities and malevolent spirits and sins committed previously. Apart from medicines and physical remedies, use of chants and charms was also in plenty (Ralph, 1896; Bloomfield, 1897).

Skin diseases are numerous and a frequently occurring health problem affecting all ages from the neonates to the elderly and cause harm in number of ways. Maintaining healthy skin is important for a healthy body. Many people may develop skin diseases that affect the skin, including cancer, herpes, cellulitis and others. Medicinal herbs and their parts are frequently used to treat these diseases (Mukhopadhyay, 2013). In Indian context, the development of skin diseases can be divided into four broad time frames: (i) the prehistoric to vedic period, (ii) the post-vedic period, (iii) medieval period, and (iv) modern period (Mukhopadhyay, 2016).

The use of plants is as old as the mankind. A deep knowledge of the herbs and their various medicinal properties can be inferred from many of the AV mantras/liturgies. The natural forces like the sun and water and human contrivances were all used therapeutically in the vedic era. The mention of leprosy (or some other disease) (AV 1–23–1–4 and AV 1–24–1–4), jaundice (AV 1–22:1–4), disease of the nail (AV 2–33–6), and many other verses dealing with wound healing (AV 4–12–4 and AV 6–57–1 etc.) are also noteworthy. Atharvavedic system of medicine is based on the theory of external disease causing agents and discusses little about the internal body mechanisms that work against diseases. It also provides the remedies through various liturgies for respiratory, cholera and other diseases.

2 Classification of microorganisms in AV

There are two distinct words mentioned in the Atharvaveda (AV) which are the krimi and kṛmi. The word kṛmi means insect (kīṭakamu) and whereas krimi means worm/germ (AV 5–23–3, 6), which multiply, enter human bodies and are visible or invisible. In other words, germs like bacteria, viruses, worms and others are referred to as krimi and various insects like kīṭa, pataṃga are referred as kṛmi. The word krimi occurs in the Atharvaveda for different macroscopic (worms) and microscopic (bacteria, viruses, fungal pathogens) organisms. Based on the above, there are two types of krimi viz., dṛṣta (visible/macroscopic) and adṛṣta (invisible/microscopic), described in the AV as designated hymns (5–23:1–13) to kill the parasitic germs. A schematic representation on the classification of microorganisms is represented in the Fig. 1.

यो अक्ष्यौऽपरिसर्पति यो नासे परिसर्पति ।

दतां यो मध्यं गच्छति तं क्रिमिं जम्भयामसि ॥

yo akṣyau parisarpati

yo nāse parisarpati ।

datāṃ yo madhyaṃ gacchati

taṃ krimiṃ jambhayāmasi ॥ (AV 5–23–3)

The krimis that are present in the eyes, nostrils, teeth are being destroyed (Griffith, 1895–1896; Bloomfield, 1897).

उत् पुरस्तात् सूर्य॑ एति विश्वदृष्टो अदृष्टहा ।

दृष्टांश्च घ्नन्नदॄष्टांश्च सर्वांश्च प्रमृणन् क्रिमीन् ॥

ut purastāt sūrya eti

viśvadṛṣṭo adṛṣṭahā ।

dṛṣṭāṃśca ghnannadṝṣṭāṃśca

sarvāṃśca pramṛṇankrimīn ॥ (AV 5–23–6)

The sun is the god who is visited by all living beings. He is destroying germs that are invisible to the eye. Both the visible (dṛaṣta) and invisible (adṛṣta) krimis are being killed by Āditya who is rising in the east (Griffith, 1895–1896; Bloomfield, 1897).

Fig. 1
figure 1

Classification of microorganisms in Atharvaveda

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3 Causes of skin disorders

The skin disorders vary greatly in symptoms and severity. They can be temporary or permanent, and may be painless or painful. Some have situational causes, while others may be genetic. Some skin conditions are minor, and others can be life-threatening. While most skin disorders are minor, others can indicate a more serious issue. Some common known causes of skin disorders include – bacteria trapped in skin pores and hair follicles, fungus, parasites, or microorganisms living on the skin, viruses, a weakened immune system, contact with allergens, irritants, or another person’s infected skin, genetic factors, illnesses affecting the thyroid, immune system, kidneys, and other body systems. Numerous health conditions and lifestyle factors can also lead to the development of certain skin disorders. Some skin conditions have no known cause (Brind’Amour, 2016).

Atharvaveda describes the skin diseases (twak roga) in the name of kilasa, palita, with the clinical picture of grey and white spots, generally from deeper layers of skin and mentions their herbal remedies. Almost all the Ayurveda saṃhitās uniformly classified kuṣṭa as mahākuṣṭa and kṣudrakuṣṭa, but there is difference of opinion about the number in each group. The historical perspectives of the twak rogas (kuṣṭa) were presented according to Ṛgveda, Atharvaveda, Caraka, Suśruta, Vāgbhaṭa, Mādhavakara and Toḍaramalla. In the doctrines of Ayurveda, the twak rogas are known by the general term kuṣṭa (Narayana, 1997). The term ‘kilasa’ occurs in the Atharvaveda and the Vājasanēyī saṃhita meaning white leprosy, in which the skin becomes spotted without ulcers, probably a type of tuberculoid leprosy.

3.1 Takman (fever and related body aches)

The vedic term takman is particular to the Atharvaveda (AV). The word takman is derived from the Sanskrit grammatical root word (dhātu)– ak + matup, ‘takati vyāpnōti śarīrē’ meaning ‘spreading in the body’. It is designated as demonic disease whose characteristics point to fever. Takman is the main disease mentioned in the Atharvaveda. There is an enormous discussion about it and five sūktas (1–12, 1–25, 5–22, 6–20, 7–116) are devoted to this disease. There are different names for the fevers of different durations–ubhayeṣu for 2 day’s fever; tritīyaka for 3 day’s fever; sadandi for a long duration fever and hāyana for a year’s fever (AV 19–39–10).

शीर्षलोकं तृतीयकं सदन्दिर्यश्च हायनः ।

तक्मानं विश्वधावीर्याधराञ्चं परा सुव ॥

śīrṣalokaṃ tṛtīyakaṃ

sadandiryaśca hāyanaḥ ।

takmānaṃ viśvadhāvīryā

dharāñcaṃ parā suva

॥ (AV 19–39–10)

The takman that returns on each third day, the one that continues without intermission, and the yearly one, ao thou, (O plant) of unremitting strength, drive away down below! (Bloomfield, 1897, p. 8).

Fever is a disease that spreads in regions. Seasonal variations are also mentioned as causes of diseases, epidemic of takman (fever) is at a high level in the rainy season and hence it is known as vārṣika.

तृतीयकं वितृतीयं सदन्दिमु॒त शारदम् ।

तक्मानं शीतं रूरं ग्रैष्मं नाशय वार्षिकम् ॥

tṛtīyakaṃ vitṛtīyaṃ

sadandimu̱ta śāradam ।

takmānaṃ śītaṃ rūraṃ

graiṣmaṃ nāśaya vārṣikam॥

(AV 5–22–13)

Destroy the takman that returns on (each) third day, the one that intermits (each) third day, the one that continues without intermission, and the autumnal one; destroy the cold takman, the hot, him that comes in summer, and him that arrives in the rainy season! (Bloomfield, 1897).

The sun dispels diseases and sickness and there are references regarding the germ killing power of sun rays mentioned in AV 2–32–1 and AV 5–23–6.

उद्यन्नादित्यः क्रिमीन् हन्तु निम्रोचन् हन्तु रश्मिभिः ।

ये अन्तः क्रिमयो गवि ॥

udyannādityaḥ krimīn hantu

nimrocan hantu raśmibhiḥ ।

ye antaḥ krimayo gavi ॥ (AV 2–32–1)

The rising sun shall slay worms, the setting sun with his rays shall slay the germs that are within the cow! (Griffith, 1895–1896; Bloomfield, 1897).

In this context, we should recall the fact that Sun was the father of the divine physicians, Aśvins. Atharvaveda is primarily a charm system in which the charms were systematically accompanied by an ‘amulet’. Thus, there are number of charms to cure number of diseases (Prasad, 2002). According to Karambelkar (1961), the word takman may have been a general term for ‘fever’ which could be classified into three types: (i) malarial fever, (ii) influenza and (iii) typhoid fever. The medicinal herb kuṣṭa is used to destroy fever. The kuṣṭa plant has a power to remedy sickness, pain in the head, affliction in the eye, and ailment of the body. The botanical description of this medicinal plant is described in detail in the section on ‘description of medicinal herbs’.

3.2 Yakṣma (consumption/tuberculosis, syphilis)

Yakṣma in the Ṛgveda (1–122–9, 10–85–31) and the Atharvaveda (2–10–5, 6; 3–31–1, 5–4–9, 7–7–2, 10–8–3, 7, 10; 12–2–1, 2; 19–36–1; 19–38–1) frequently denotes 'illness’, in general, perhaps as rendering the body emaciated. Yakṣma is the regular Atharvan term for disease. AV mentions that it is the general internal disease found both in humans and cattle (AV 8–7–15, 12–2–1). It is characterized by entering and possessing each and every part of the body (AV 6–85–1, 9–8–7 & 9). It causes disintegration of the limbs, fever in the limbs, pain in heart and in all parts of the body (AV 5–30–8 & 9, 9–8–5, 13–19, 21 & 22). Majority of writers on Vedic literature believe that yakṣma referred to a class of diseases whose principal characteristics were those of consumption/tuberculosis (Prasad,  2002).

नडमा रोह न ते अत्र लोक इदं सीसं भागधेयं त एहि ।

यो गोषु यक्ष्मः पुरुषेषु यक्ष्मस्तेन त्वं साकमधराङ् परेहि ॥

naḍamā roha na te atra loka idaṃ sīsaṃ

bhāgadheyaṃ ta ehi ।

yo goṣu yakṣmaḥ puruṣeṣu

yakṣmastena tvaṃ sākamadharāṅ parehi ॥

(AV 12–2–1)

Together with consumption in the cattle, consumption in our men, in company with that do thou go forth downward (Griffith, 1895–1896; Bloomfield, 1897).

A hundred kinds of yakṣma are referred to in the Vājasanēyī saṃhitā (12–97) and ayakṣma in the Kāṭhaka saṃhitā (17–2). In the Yajurveda saṃhitās [TS 2–3–5; MS 2–2–7; KS 11–3; SB 4–1–3(9)] an explanation is provided for the origin of the word yakṣma, which is distinguished as of three kinds, namely the ‘rājayakṣma’ means ‘royal yakṣma’, ‘pāpayakṣma’ means ‘evil yakṣma’, and the ‘jāyānya’, most probably 'syphilis’ according to Macdonell and Keith (1982). The second of the series is elsewhere unknown, and can hardly be defined, for it merely means 'serious or deadly disease’. The germ/krimi of yakṣma (consumption) arising from excessive cohabitation, flies like a bird from one place to the other and enters the body of a man (AV 7–76–4). Below is the AV liturgy:

पक्षी जायान्यः पतति स आ विशति पूरुषम्।

तदक्षितस्य भेषजमुभयोः सुक्षतस्य च ॥

pakṣī jāyānyaḥ patati

sa ā viśati pūruṣam ।

tadakṣitasya bheṣajam

ubhayoḥ sukṣatasya ca ॥

(AV 7–76–4)

Scrofula flies borne on by wings, it penetrates and holds the man. Here is the cure, the chronic and the transient (Griffith, 1895–1896; Bloomfield, 1897).

Scrofula, also called cervical tuberculosis lymphadenitis, is a type of tuberculosis infection. It's caused by the same bacteria (Mycobacterium tuberculosis) that cause pulmonary tuberculosis (TB). Tuberculosis is a highly infectious bacterial illness. Atharvaveda vividly explained this as rājayakṣma (king’s evil) in the name of ‘jāyānya’ (AV 7–76–3 and AV 7–76–5), pāpma (AV 5–22–12) and discusses very elaborately about two main causative factors, varieties (AV 7–76–4) and complications (AV 7–76–3). The treatment for yakṣma (roga cikitsā) is explained in the AV (3–11:3–5). This is said to lead to death and found to be common among people of durācara (bad habits) (Narayana, 1995). A charm to cure scrofulous pustules and scrofula is mentioned in the AV 7–76–3. The word ‘jāyānya’ mentioned in AV also resembles consumption/tuberculosis and it breaks ribs, settles in the lungs, harbours in the back and springs from excessive sexual intercourse (AV 7–76–3).

यः कीकसाः प्रशृणाति तलीद्यऽमव॒तिष्ठति ।

निर्हास्तं सर्वं जायान्यं यः कश्च ककुदि श्रितः ॥

yaḥ kīkasāḥ praśṛṇāti

talīdya'mavatiṣṭhati।

nirhāstaṃ sarvaṃ jāyānyaṃ

yaḥ kaśca kakudi śritaḥ॥ (AV 7–76–3)

The  Jāyānya that crushes the ribs, that which passes down to the sole of the foot, and whichever is fixed upon the crown of the head, I have driven out every one (Griffith, 1895–1896; Bloomfield, 1897).

शर्म यच्छत्वोषधिः सह देवीररुन्धती ।

करत् पयस्वन्तं गोष्ठमयक्ष्मां उत पूरुषान्॥

śarma yacchatvoṣadhiḥ

saha devīrarundhatī ।

karat payasvantaṃ goṣṭham

ayakṣmāṃ uta pūruṣān ॥

(AV 6–59–2)

Let the ōṣadhi Arundhatī allied with Gods give us defending aid; avert Yakṣma (consumption) from our men and make our cow-pen rich in milk (Griffith, 1895–1896; Bloomfield, 1897).

After bringing the medicinal plants, the yakṣma disease is getting terrified. The disease is able to fly and scatter as though a lion's roar or fire dismayed them. The digestive fire (vaiśvānarāgni) in the stomach displaying with drugs is devastating the human beings disease.

In the AV 8th kāṇḍa, 7th sūkta, there are 28 verses/hymns which explain the characteristics of twenty one (21) medicinal herbs and trees that are revealed for the treatment of yakṣma and related diseases.

3.3 Kuṣṭa, Kilasa, Palita, Vitiligo (leprosy and allied skin disorders)

The word kuṣṭa is derived from the Sanskrit grammatical root word (dhātu)– kuś + kathan, ‘kuṣṇāti rōgaṃ dēhaṃ vā’ meaning ‘the disease leprosy torturing the body’. The term kuṣṭa is revealed in the Atharvaveda saṃhitā. It is described in the kāṇḍa 1, sūktas 23 and 24, with 1–4 hymns in each sūkta. Like other ancient medical texts in other parts of the world, the term kuṣṭa was probably used to represent a number of skin ailments along with leprosy (Mycobacterium leprae) of the modern sense. Three words ‘śvitra’, ‘kilasa,’ and ‘kuṣṭa’ were used for it. Kilasa is the name of 'white leprosy' in the Atharvaveda (1–23–1). It resulted in the appearance of grey (palita) and white (śukla, śvēta) spots all over the body. The etiology of kuṣṭa is stated in the AV 1–23–4. It affects the bone tissue (asthi), muscle tissue (māmsa), adipose tissue (mēda) etc., and the essential elements that constitute the human body (dhātus).

नक्तंजातास्योषधे रामे कृष्णे असिक्नि च ।

इदं रजनि रजय किलासं पलितं च यत् ॥

naktaṃjātāsyoṣadhe

rāme kṛṣṇe asikni ca ।

idaṃ rajani rajaya kilāsaṃ

palitaṃ ca yat ॥

(AV 1–23–1)

Oh oṣadhis! You are all born in the night. Remove the scales on the infected organ/skin and apply it with your color. Similarly, smear the bleached hair with your color. So, rajani, re-colour thou these ashy spots, this leprosy (Griffith, 1895–1896; Bloomfield, 1897).

Here in the above mantra/liturgy, the medicinal herbs namely, rāma (vākucī–Psoralea corylifolia), kṛṣṇa (bhṛṅgarāja–Eclipta alba), asikni (Nīli–Indigofera tinctoria) and rajani (haridra–Curcuma longa) are revealed in the AV for the treatment of kilasa and palita skin disorders.

अस्थिजस्य किलासस्य तनूजस्य च यत् त्वचि।

दूष्या कृतस्य ब्रह्मणा लक्ष्म श्वेतमनीनशम्॥

asthijasya kilāsasya

tanūjasya ca yat tvaci ।

dūṣyā kṛtasya brahmaṇā

lakṣma śvetamanīnaśam ॥

(AV 1–23–4)

The disease kilasa (leprosy) infection, on the skin, sprung from the body and from the bones. It is destroyed with the invocation of the mantra/liturgy (Griffith, 1895–1896; Bloomfield, 1897).

The plant nīli (Indigofera tinctoria) is described in two hymns of the Atharvaveda as a dark coloured plant (AV 1–23 and 1–24). This plant is used against white leprosy or svētakuṣṭa. It is believed that in the Atharvaveda the darkness of the plant nīli removes the white spot of the body. In these hymns white leprosy is called as kilasa and gray spots are called palita. For warding off this disease, the medicinal herbs haridra, rāma, kṛṣṇa are used along with plant nīli or asikni. A paste prepared from these plants or their leaves would give black colour to the skin (AV 1–23.1–3). Kauśika saṃhita describes detail use of the nīli plant in 26.22–24. Other plants nakthajata (AV 1–23–1), asurī or śyāma and brahma (AV 1–24–4) are  also mentioned as the medicine for  leprosy (kuṣṭa roga).

3.4 Classification of kuṣṭa roga in Ayurveda

The classification of kuṣṭa into seven types in the Caraka saṃhitā and 18 (seven mahākuṣṭa and 11 kṣudrakuṣṭa) in the Suśruta samhitā represents the astute observation of the ancient Indian physicians. Interestingly, kuṣṭa and kilasa (be it leprosy or vitiligo) was clearly declared not to be an inheritable disorder (Mukhopadhyay, 2016). The description of various forms shows that these included diseases like Ichthyosis, Dermatophytosis, Leucoderma, Psoriasis, Eczema, Seborrhoeic Dermatitis etc. (Banerjee, 1976). Vitiligo is a pigmentation disorder, in which pigmentation cells (melanocytes) of skin are destroyed, which results in smooth, white patches in the midst of normally pigmented skin. People with vitiligo may also associate with eye and other diseases. Ayurveda has considered all the skin diseases under a common head known as kuṣṭharoga. The term kuṣṭa, in English known as leprosy, literally means discoloration, disgrace, disfiguration of the normal skin texture. Amarasimhakavi (1951) in his Amarakośa, the lexicographical work, defines the term kuṣṭa as following:

व्याधिः कुष्ठं पारिभाव्यं व्याप्यं पाकलमुत्पलं ।

शम्खिनी चोरपुष्पी स्यात्केशिन्यथ वितुन्नकः ॥

vyādhiḥ kuṣṭhaṁ pāribhāvyaṁ

vyāpyaṁ pākalamutpalaṁ ।

śamkhinī corapuṣpī

syātkeśinyatha vitunnakaḥ ॥

The herb, Saussurea costus (Falc.) Lipsch., (commonly called as kuṣṭa), is described in the kāṇḍa 5, sūkta 4, with 1–10 hymns; and in the kāṇḍa 19, sūkta 39 with 1–10 hymns. It is used in Ayurveda for the treatment of several skin disorders and also for other ailments of the body. Sharma (1969) has compiled its uses as mentioned in Atharvaveda. It has been used in takman (fever of all kind); śiraḥ śool ukta jvara (headache with fever); tṛtyāya jvara (fever after every third day); santatajvara (long fever); ekahik-jvara (single fever); kafa-roga (cough);  krimi-roga (worm remover); śiroroga (headache); śirovedanā (head pain); dṛṣṭi-roga (eyesight disease); tvagroga (skin diseases); prāna-vāyu triguṇata (breathing disease); vyān-vāyu viguṇata (a kind of breathing trouble). Apart from the above, it was also used as balavardhaka (tonic); vīryavardhaka (increaser of semen) and in jaundice. And, it was also used as incense and in havana sāmigri with other aromatic ingredients. The geographical distribution, botanical history, chemical constituents and therapeutic uses of the medicinal herb, kuṣṭa, which is an ancient and important medicinal plant native to Kashmir revealed in the Atharvaveda (AV) have been extensively discussed (Akbar, 2020; Prasad & Subhaktha, 2002; Rathore et al., 2021; Shah, 2019; Singh & Singh, 2019).

3.5 Śvitra

The word śvitra is derived from the Sanskrit grammatical root word (dhātu) – śvit + rak, śvētatē śuklō bhavati– which means white patch; śvētakuṣṭhamu (white leprosy). Śvitra is found as an adjective in the Pāñcaviṃśa Brāhmaṇa (12–11–11) in the sense of 'afflicted with white leprosy’. So śvitra is a disease where white patches appear on the body. The disease has got a special importance as it causes ugliness of the body. Probably keeping this in mind, the Ayurveda described the disease along with kuṣṭa. The important classical texts of Ayurveda such as Caraka saṃhitā, Suśruta saṃhitā, Aṣtāṅga hṛdaya etc. clearly mention the treatment of śvitra along with its classification and prognosis. Most of them use śvitra and kilasa as synonyms. Śvitra is known by different names like (i) kilasa or kilasam where normal colour of skin is destroyed (Atharvaveda), (ii) palitam referring particularly to whiteness of the scalp hair (Atharvaveda), (iii) alasa (Aitareya Brāhmaṇa 6–33–5), (iv) dāruna, caruna, śvitra (Caraka saṃhitā 7–173) and (v) kilasi (meaning spotted dear) Max Muller’s commentary on Ṛgveda.

In Atharvaveda, four important medicinal plants have been mentioned for the treatment of śvitra (kilasa) in the two hymns of AV by their descriptive epithets. They are: rāma (bākucī—Psoralea corylifolia), kṛṣṇa (bhṛiṅgarāja–Eclipta alba), asikni (Nīlī - Indigofera tinctoria), indravaruṇi  (Citrullus colocynthis) and rajani (haridra–Curcuma longa). The botanical descriptions of these medicinal plants are detailed in the section, ‘description of medicinal herbs’.

4 Descriptions of medicinal herbs

Several Indian origin medicinal plants that are revealed in the Atharvaveda are still being used as major ingredients of various Ayurvedic products. In this research article, some of the medicinal herbs used for the treatment of skin diseases with their common names in Sanskrit, botanical description and chemical constituents are described below:

4.1 Achyranthes aspera Linnaeus (Family: Amaranthaceae; Sanskrit names: apāmārga, adhoghanta, adhvaṣalya, aghamārgava, aghāta, apāngaka, camatkāra, dhamārgava)

It is an erect or procumbent, annual or perennial herb with spreading branches, usually up to 1 m tall, often with a herbaceous woody base. The stem is stiff, quadrangular, ribbed, pubescent, branched from the base, often reddish purplish tinged; leaves opposite, thick, ovate elliptic or obovate rounded, 4–12 cm long and up to 8 cm wide, velvety tomentose. The flowers are greenish-white, small, numerous, in axillary or terminal spikes up to 75 cm long, fruit utricle, oblong-cylindric, truncate at apex, rounded at base and seeds are reddish-brown, sub-cylindrical (Fig. 2a–d). The chemical constituents of Achyranthes aspera contain triterpenoid saponins which possess oleanolic acid as the aglycone. Ecdysterone, an insect moulting hormone, and long chain alcohols are also found in this herb (Indian Herbal Pharmacopia, Vol. II, p. 5).

Fig. 2
figure 2

Apāmārga (Achyranthes aspera L.) a herbs in flowering b inflorescence close-up, c excised root pieces, d seeds

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4.2 Citrullus colocynthis (L.) Schrad. (Family: Cucurbitaceae; Sanskrit names: aindri, atmarakṣa, bṛhadvaruṇi, bṛhatphala, citrāla, citrapāla, gavākṣi, indravaruṇi, mṛgabojani, mahēndravaruṇi)

Citrullus colocynthis is a desert viny plant that grows in sandy, arid soils. Roots are large, fleshy, and perennial, leading to a high survival rate. Vine-like stems spread in all directions. Leaves are palmate and angular with three to seven divided lobes. Flowers are yellow and solitary in the axes of leaves and are borne by yellow-greenish peduncles. Corolla five-lobed, sub-campanulated; male and female flowers are separate; stamens five; ovary three-carpeled, each carpel bears six seeds. Fruit is smooth, spherical 5–10-cm-diameter, extremely bitter taste, each plant produces 15 to 30 fruits. Seeds are grey and 5 × 3 mm wide (Fig. 3a–d). The oil content of Citrullus seeds is consisting of 67–73% linoleic acid, 10–16% oleic acid, 5–8% stearic acid, 9–12% palmitic acid and 3% cucurbitacin. In addition, the seeds contain a high amount of arginine, tryptophan, and the sulfur-containing amino acids.

Fig. 3
figure 3

Indravaruṇi [Citrullus colocynthis (L.) Schrad.] a desert vine crop, b flower close-up, c spherical fruits, d seeds

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4.3 Clitoria ternatea L. (Family: Fabaceae/Leguminosae; Sanskrit names: aparājita, adrikārṇi, asphoṭa, ghṛstih, girikarṇi, mahāṣveta, rādhā, śankhapuṣpi, śveta)

It is a perennial herbaceous climbing plant, glabrescent and slender twiners. Leaves are elliptic, obtuse and flowers vivid deep blue/white/violet/pink, solitary; upside down, keel petal appears on the top rather than the underside. Pods compressed, entire, oblong, pubescent, 5–9 cm (2.0–2.8 in) long, flat pods, edible when tender; seeds six to ten in each pod (Fig. 4a–d). Chemical compounds isolated from Clitoria ternatea include various triterpenoids, flavonol glycosides, anthocyanins and steroids. Cyclic peptides known as cliotides have been isolated from the heat-stable fraction of the extract. The blue colour of C. ternatea is a result of various anthocyanins, most importantly ternatins—polyacylated derivatives of delphinidin 3,3', 5'-triglucoside (Da-T) (Nguyen et al., 2011).

Fig. 4
figure 4

Aparājita (Clitoria ternatea L.) a climbing herb, b flower close-up, c pods with seeds, d dried seeds

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4.4 Curcuma longa L. (Family: Zingiberaceae; Sanskrit names: haridra, rajani, niṣāhaldi, halada)

Turmeric is a perennial herbaceous plant reaching up to 1 m (3′3′′) tall; rhizomes highly branched, yellow to orange, cylindrical, aromatic. Leaves are alternate and arranged in two rows, with leaf sheath, petiole 50–115 cm (20′′–45′′) long, leaf blade 76–115 cm (30′′–45′′) long, oblong to elliptical. Flowers are hermaphrodite; sepals three; petals three, bright yellow, fused into corolla tube. Fruit capsule opens with three compartments (Fig. 5a–d). Phytochemical constituents of turmeric include diarylheptanoids, a class including numerous curcuminoids, such as curcumin, demethoxycurcumin, and bisdemethoxycurcumin. Curcumin constitutes up to 3.14% of assayed commercial samples of turmeric powder (the average was 1.51%); curry powder contains much less (an average of 0.29%). About 34 essential oils are present in turmeric, among which turmerone, germacrone, atlantone, and zingiberene are major constituents (Nelson et al., 2017). Turmeric is a plant known by its medicinal use from the Vedic period, and is widely used in herbal and complementary medicine. In a recent research report on the current knowledge on Curcumin’s effects on skin conditions alongside with its bioavailability and safety profile is documented (Vollono et al., 2019).

Fig. 5
figure 5

Rajani (Curcuma longa L.) a crop, b flowering, c rhizomes, d Haldi powder

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4.5 Eclipta alba (L.) Hassk. (Family: Asteraceae/Compositae; Sanskrit names: bhṛnga, bhṛngarāja, kesarāja, kayyonni, mārkava, tekarajah)

The plant is a creeping and ascending herb; stem cylindrical or flat, rough due to appressed white hairs; leaves are opposite, sessile to sub-sessile, wide, oblong, lanceolate, sub-entire, acute to sub-acute and strigose with appressed hairs on both surfaces. Flowers are white, solitary ovate, obtuse or acute and strigose with oppressed hairs; stamens five, filament epipetalous, free, anther united into a tube with base obtuse. Ovary is inferior and unilocular with one basal ovule. Fruit is achenial cypsela, one seeded, cuneate, with a narrow wing and brown in colour (Fig. 6a–d). The chemical constituents of Eclipta alba contain various phytochemicals, such as coumestans, polypeptides, polyacetylenes, thiophene derivatives, steroids, sterols, triterpenes, and flavonoids (Chung et al., 2017).

Fig. 6
figure 6

Bhṛngarāja [Eclipta alba (L.) Hassk.] a plant, b flower close-up, c drying seeds, d Bhṛngarāja powder

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4.6 Indigofera tinctoria L. (Family: Fabaceae/Leguminosae; Sanskrit names: anjanakesika, asita, aśikni, kāli, kāla, kālakeṣi, nīlī, nīlika, nīlini, ranjani, rangapatri and śyama)

Indigofera tinctoria is an erect shrub, 1.5 m tall, many-branched from base, appressed-pubescent under shrubs. Leaf rachis are around 8 cm long and leaf-lets around 7–11 cm, opposite, rarely sub-opposite, obovate-oblong, obtuse, apiculate. Raceme ~ 4 cm long, 15–20-flowered; calyx incised to half-way; pod linear, slightly curved, sparsely hairy, deflexed, 6–10-seeded, 2–3 cm long (Fig. 7a–d). Dye is obtained from the processing of the plant's leaves. They are soaked in water and fermented in order to convert the glycoside indican naturally present in the plant to the blue dye indigotin. The precipitate from the fermented leaf solution is mixed with a strong base such as lye. The chemical constituents extracted from this plant are rotenoids deguelin, dehydrodeguelin, rotenol, rotenone, tephrosin and sumatrol (Perkin & Bloxam, 1907).

Fig. 7
figure 7

Nīlī (Indigofera tinctoria L.) a shrub, b flowers close-up, c drying pods,  d indigo powder

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4.7 Psoralea corylifolia L. (Family: Fabaceae/Leguminosae; Sanskrit names: bākuci, vākuci, āvalguja, kṛṣṇaphala, pootiphali, kuṣtāgni, somarājñī, suparnika, somavalli, kālameṣi)

It is an annual, 50–90 cm tall plant. Leaves simple, ovate, sub-cordate at base, petiole 2.5 cm long, dentate, pubescent on both surfaces; raceme 5.5 cm long-peduncled; flowers 12–20, bluish-purple; pod ovoid or oblong, one-seeded. The most distinctive feature is the occurrence of minute brown glands which are immersed in surface tissue on all parts of the plant, giving it a distinctive and pleasant fragrance (Fig. 8a–d). The chemical constituents of Psoralea corylifolia extract contain numerous phytochemicals, including flavonoids (neobavaisoflavone, isobavachalcone, bavachalcone, bavachinin, bavachin, corylin, corylifol, corylifolin and 6-prenylnaringenin), coumarins (psoralidin, psoralen, isopsoralen and angelicin), meroterpenes (bakuchiol, and 3-hydroxybakuchiol) (Zhao et al., 2005).

Fig. 8
figure 8

 Bākūcī (Psoralea corylifolia L.) a plants, b flowering in clusters, c drying seeds, d seeds

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4.8 Saussurea costus (Falc.) Lipsch. (Family: Asteraceae/Compositae; Sanskrit names: kuṣṭa, dravyaguna vijñāna, nadhāriṣa, naghāmāra and viśvabheṣaja)

Saussurea costus is 1–2 m height plant. Leaves with cauline, small, pubescent, irregularly toothed while radical leaves are very large, triangular with the long-winged petiole. Roots are often 50–60 cm long and 15–30 cm thick with a camphoraceous aromatic smell. Roots are cut into small pieces and dried indirectly over the slow and indirect fire and to form the crude drug kuth of the market (Fig. 9a–d). In the field, Arctium lappa (Burdock) is often mistaken for Saussurea lappa due to its large leaves. It is headed with dark bluish with bluish-purple flowers, achene compressed, curved upwards, pappus-hairs brown. Most pharmacologically active substances present in roots of kuṣṭa are sesquiterpenes and sesquiterpene lactones; other compounds include glycosides, anthraquinones, chlorogenic acid, β-costic acid, daucosterol, β-sitosterol, and saussureamines A to E.

Fig. 9
figure 9

Kuṣṭa [Saussurea costus (Falc.) Lipsch.] a plant, b flowers in clusters, c drying seeds, d Sliced root pieces

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4.9 Sida cordifolia L. (Family: Malvaceae; Sanskrit names: arundhati, badiyalaka, bāla, baladaya)

Sida cordifolia is an erect perennial that reaches 50–200 cm (20ʺ–79ʺ) tall, with the entire plant covered with soft white felt-like hair. Stems are yellow-green, hairy, long, and slender; leaves oblong-ovate, covered with hairs, and 3.5–7.5 cm (1.4ʺ–3.0ʺ) long by 2.5–6 cm (0.98ʺ–2.36ʺ) wide. Flowers are dark yellow, sometimes with a darker orange center; calyx hairy 5-lobed; corolla yellow, 5-lobed. Fruits are 6–8 mm wide, split into 9–11 mericarps (one-seeded portions) when mature; seeds ~ 2 mm across, dark brown or black, smooth (Fig. 10a–d). Phyto-constituents such as alcoloids, β-phenethylamine, ephedrine, pseudoephedrine, S-(+)-Nb-methyltryptophan methyl ester, hypaphorine, vasicinone, vasicinol, choline, and betaine. The roots and stems contain the alkaloid ephedrine. Also, two flavanones and two phytosterols have been isolated from this plant (Ghosal et al., 1975).

Fig. 10
figure 10

Arundhati (Sida cordifolia L.) a entire plant, b flowering stage, c drying fruits, d seeds

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5 Conclusions

The study of Vedic, Ayurvedic texts and ancient treatises concerning medical world reveals that the skin diseases are prevailing from Vedic period. The social awkwardness due to these diseases and their therapeutic aspects are mentioned in these treatises. Among the four Vedas, the Atharvaveda provides more information related to the various diseases prevalent during that period. The mention of leprosy and other skin diseases (1–23:1–4 and 1–24:1–4), disease of the nail (2–33–6), jaundice (1–22–1, 1–22–4) and many other verses dealing with wound healing etc. (4–12–4, 6–57–1) are also noteworthy. The impact of Ayurveda on the then Indian Society and intermingling of ideas between medical and other social or religious sciences can be ascertained from such descriptions. In the doctrines of Ayurveda, the twak rogas are known by the general term kuṣṭa. Atharvaveda describes the twak rogas in the name of kilasa, palita, having grey and white spots, generally from deeper layers of skin and referred their herbal remedies. Almost all the Ayurvedic saṃhitās uniformly classified kuṣṭa (leprosy) as mahakuṣṭa and kṣudrakuṣṭa, but there is difference of opinion about number in each group. In Atharvaveda, there are special hymns dedicated to the praise of herbs like jaṅgiḍa (Oroxylum indicum Vent), kuṣṭa (Saussurea lappa C.B. Clarke), rohinī (Ficus infectoria), apāmārga (Achyranthes aspera Linn.) and others. It is observed that the Atharvaveda recommends one medicinal herb to be used with charm for one disease. Using the knowledge from Atharvaveda, the later ayurvedic saṃhitās adopted using combination of herbs for the treatment of skin diseases. The examples of such treatments, are the usage of black seeds like vākucī (Psoralea corylifolia) together with bhṛṅgarāja (Eclipta alba), indravaruṇi (Citrullus colocynthis) and rajani (Curcuma longa) are recommended for the cure of śvitra roga. Four plants are recommended for the treatment of kilasa and palita skin disorders in the two hymns of Atharvaveda by their descriptive epithets– rāma (dark, Psoralea corylifolia), kṛṣṇa (black or stable, Eclipta alba), asikni (dusky, Indigofera tinctoria) and rajani (yellow, Curcuma longa).

The therapeutic herbs have great potential to cure different kinds of skin diseases. Almost 80% of people in India depend on traditional health care and use different plant based products for curing skin related problems. Compared with the conventional allopathic drugs, they have relatively low cost and can be of great benefit to the population of India in general and poor people in particular. Herbs are a rich source of active ingredients and can be safer and cost effective treatment for skin diseases ranging from rashes to the dreadful skin cancer. An increasing amount of evidence suggests that Curcumin (Curcuma longa L.) may represent an effective agent in the treatment of several skin disorders. The possible use of Curcumin in combination with traditional drugs and the formulations of novel delivery systems represent a very promising field for future applicative research.

The conservation of these plants as revealed in the Vedas with the help of local participation and carrying out of extensive research to broaden the prospects of herbal drugs in various diseases treatment is the need of the hour. ‘Śataṃ hyasya bhi̱ṣajaḥ̍ sahasramu̱ta vī̱rudhaḥ̍’ ॥ – The AV 2–9–3 speaks about a patient as, ‘He has attained attainments. He has achieved the strong hold of the living. For he now has a hundred physicians are his and also a thousand plants’.