Medicinal plants of Tamil Nadu (Southern India) are a rich source of antiviral activities

Figures & data

Table 1.  Relevant characteristics of the species used in this study.

Family/species	Plant part	Traditional use
Acanthaceae
Rungia repens Nees	Aerial parts	Juice applied on the skin to treat skin diseases including itching of the skin.
Rhinacanthus communisNees	Aerial parts	Paste of the leaves is applied externally to treat eczema and herpes.
Apocyanaceae
Wrightia tinctoria R. Br.	Aerial parts	Leaves are used to treat various skin disorders including herpes, psoriasis and nonspecific dermatitis.
Aristolochiaceae
Aristolochia indica L.	Aerial parts	Paste of the aerial part is mixed with neem leaf and burned, the fumes are inhaled to treat migraine.
Asclepiadaceae
Pergularia daemia (Forsskal) Chiov.	Aerial parts	Decoction from the aerial part is taken internally to get relief from fever.
Gymnema sylvestre R. Br.	Aerial parts	Powder made from the aerial parts is taken internally to treat diabetes. Traditional Ayurvedic medicine uses Gymnema to treat a variety of other disorders as well, including digestion problems, cough, constipation, and malaria.
Asteraceae
Wedelia chinensis (Osbeck) Merr.	Aerial parts	Widely used in India to treat jaundice and other liver and gall bladder ailments.
Sphaeranthus indicus L.	Aerial parts	Paste is applied externally to treat skin disease and leprosy.
Bombacaceae
Durio zibethinus L.	Leaves	Leaf juice is applied on the head of a patient with fever. The leaves are employed in medicinal baths to treat jaundice. Decoctions of the leaves and fruits are applied to swellings and skin disease.
Boraginaceae
Trichodesma indicum R.Br.	Aerial parts	The traditional healers use this herb in treatment of diseases related to urinary system and also to treat patients having the problem of piles specially the bleeding piles.
Cleomaceae
Cleome pentaphylla L.	Aerial parts	The juice of the leaves has been used to relieve earache and itching.
Caesalpiniaceae
Caesalpinia bonduc (L.)Roxb.	Aerial parts	The seeds are bitter and they are useful in treating inflammation, cough, asthma, leprosy, skin diseases, dysentery, colic and intestinal worms.
Cassia alata L.	Leaves	Crushed leaves are rubbed on ringworm-affected skin, for immediate relief.
Convolvulaceae
Evolvulus alsinoides L.	Aerial parts	Decoction made from the aerial part is taken internally to treat dysentery, falling and graying of hair and to treat fever.
Cucurbitaceae
Mukia maderaspatana (L.) M. Roemer	Aerial parts	The leaves are used as a poultice in treating skin eruptions. It is used internally in the treatment of gonorrhea.
Euphorbiaceae
Ricinus communis L.	Aerial parts	The decoction of the leaf is used as hair tonic/alopecia.
Jatropha curcas L.	Aerial parts	Paste of young leaf is applied to treat cuts and wounds.
Indigofera tinctoria L.	Aerial parts	Indigofera tinctoria is heated with Cansjera rheedi Gmel. (Opiliaceae), gingili, castor and coconut oil and taken internally for 40 days to treat poisonous bites.
Fabaceae
Clitoria ternatea L.	Aerial parts	Paste made from the aerial part is taken internally to treat pulmonary tuberculosis.
Clusiaceae
Garcinia mangostana L.	Rind	A portion of the rind is steeped in water overnight and the infusion is given as a remedy for chronic diarrhea in adults and children.
Lamiaceae
Leucas aspera Spr.	Aerial parts	Leaves and flowers are used for inhalation through nose to cure migraine. In addition, two drops of the juice of the flowers is useful as a nasal drop. Juice of the leaves is used as local application to treat psoriasis, chronic skin eruptions and chronic rheumatism.
Lythraceae
Woodfordia fructicosa Kurz.	Aerial parts	The leaves are used in bowel complaints and hemorrhages.
Malvaceae
Abutilon indicum G. Don.	Aerial parts	Leaves of Abutilon indicum were traditionally used to treat bronchitis, gonorrhea, and as mouthwash in toothache.
Papaveraceae
Argemone mexicana L.	Aerial parts	The fresh yellow, milky, acrid sap contains protein-dissolving substances and has been used in the treatment of warts, cold sores, cutaneous affections, skin diseases and itches.
Pedadiaceae
Pedalium murex L.	Aerial parts	Stem and leaves are soaked and stirred in milk for few minutes until the milk becomes thick and is taken internally to treat diabetes, urinary irritations, uterine and puerperal diseases and local ulcers.
Rubiaceae
Morinda pubescens J. E. Sm.	Aerial parts	Decoction of this plant is taken internally to treat diarrhea and dysentery
Oldenlandia corymbosa L.	Aerial parts	Decoction made from the whole plant with Evolvulus alsinoides, Coscinium fenestratum (Gaertn.) Colebr. (Menispermaceae) is used to treat cough. The traditional healers use it both externally as well as internally in the treatment of Insomnia.
Spermococe hispida L.	Aerial parts	Decoction of the aerial part is taken to get relief from colic, flatulence and general debility.
Sapindaceae
Cardiospermumhalic-acabum L.	Aerial parts	Paste made from leaves is taken internally to treat chronic rheumatism and arthritis.
Solanaceae
Datura metel L.	Aerial parts	The decoction of leaf is used to counter ringworm, tooth ache, rheumatism, constipation and asthma.
Verbenaceae
Clerodendrum inerme (L.) Gaertn	Aerial parts	Clerodendrum inerme leaf juice is used to get relief from fever; flower juice is used to treat eye infection. Leaves are pounded with coconut oil, and applied on the affected area to treat skin rashes. Seed and root powder neutralizes fish poison.
Vitex trifolia L.	Aerial parts	Leaf, fruit and root are used to cure rheumatism, contusion and fever; they are also used as diuretic and counter dermatitis and eczema.

Figure 1.  Anti-HSV plant extracts (virucidal protocol). Results for each of the indicated species are plotted as reciprocals of the MIC (minimum inhibitory concentration) in μg/mL. The higher the bar, the greater the antiviral activity. Thus a value of 2.0 represents an MIC of 0.5 μg/mL (or less in some cases) other plant species showed little or no activity.

Figure 2.  Anti-coronavirus (MCV) extracts (virucidal protocol). Results for each of the indicated species are plotted as reciprocals of the MIC (minimum inhibitory concentration) in μg/mL. The higher the bar, the greater the antiviral activity. Thus a value of 2.0 represents a MIC of 0.5 μg/mL (or less in some cases) other plant species showed no activity.

Figure 3.  Anti-calicivirus (FCV) extracts (virucidal protocol). Results for each of the indicated species are plotted as reciprocals of the MIC (minimum inhibitory concentration) in μg/mL. The higher the bar, the greater the antiviral activity. Other plant species showed no activity.

Figure 4.  Antiviral activities (pre-exposure protocol). Results for each of the indicated species are plotted as reciprocals of the MIC (minimum inhibitory concentration) in μg/mL. The higher the bar, the greater the antiviral activity. Other plant species showed no activity.

Figure 5.  Antiviral photosensitizers (virucidal protocol). MIC values were measured against HSV and MCV (virucidal protocol) both in light and in dark (details in Materials and methods section), and the results plotted as reciprocals as in Figure 1. All extracts except O. corymbosa and G. mangostana showed marked light-enhanced or light-dependent activity typical of photosensitizers.

Figure 6.  Summary of percentage of species with specific antiviral activities against each virus.