S Malhotra, A Pal Singh
ayurveda, indian medicinal plants, pharmacology, phytochemicals
S Malhotra, A Pal Singh. A Review of Pharmacology of Phytochemicals from Indian Medicinal Plants. The Internet Journal of Alternative Medicine. 2006 Volume 5 Number 1.
In recent years, research on medicinal plants has attracted a lot of attention globally. Large body of evidence has accumulated to demonstrate promising potential of medicinal plants used in various traditional, complementary and alternative systems. Several Indian medicinal plants have been studied for pharmacological activity in recent years. To understand the mechanism of action, the researchers have worked at molecular levels and several significant phytochemicals have been isolated. The present review is aimed at compiling data on promising phytochemicals from Indian medicinal plants that have been tested in various disease models using modern scientific methodologies and tools.
Medicinal herbs are significant source of synthetic and herbal drugs. In the commercial market, medicinal herbs are used as raw drugs, extracts or tinctures. Isolated active constituents are used for applied research. For the last few decades, phytochemistry (study of plants) has been making rapid progress and herbal products are becoming popular.
To facilitate the readers to look at their areas of interest, we have tried to discuss potential phytochemcials in this article. In the review pharmacological investigations on phytochemicals have been discussed according to human anatomy.
Bergenin and neobergenin belongs to isocoumarin group of phytochemicals. They have been isolated from leaves and roots of
Luvangetin, a pyranocoumarin isolated from seeds of
Kutkins isolated from
Hepatoprotective activity of C-phycocyanin isolated from
Ursolic acid isolated from leaves of
Bioassay guided activity of fruit extract of Terminalia belerica identified 3, 4, 5-trihydroxy benzoic acid (gallic acid), as hepatoprotective principle 8.
Andrographolide produced dose dependent chloretic effect evidenced by increase in bile flow, bile salt and bile acids in animal models. The cholretic effect of
Chebulin an anthraquinone glycoside found in flowers of
Anti diarrheal activity of piperine, the principle alkaloid of
Experiments conducted with Tylpohorine a phenanthroindalizidine alkaloid present in
Guggulsterones found in
Jatamansone a sesquiterpene ketone found in
Bacosides belong to group of compounds known as triterpenoid saponins 18. They are considered to be active constituents of
Extensive pharmacological studies with standardized extracts of
Ginkgo biloba is well known for its pharmacological activities. The medicinal plant contains bioflavonoids, pronathocyanidins, diterpenes and a toxic compound ginkgolic acid. In an experimental study, aimed at anxiolytic activity of ginkgolic acid conjugates (including several salicylates) demonstrated significant anxiolytic activity. In contrast, toe commercial preparations EGb 761 and Ginkocer (devoid of ginkgolic acid conjugates failed to evoke significant anxiolytic activity 22. The study was concluded that ginkgolic acid conjugates might be the active constituents of
Gossypin is a bioflavonoid obtained from yellow petals of
Gossypin was found to significantly reduce the rat paw, edema and the increased vascular permeability induced by various phlogistic agents. It produced significant inhibition of the accumulation of pouch fluid and granulation tissue formation in the carrageenin induced granuloma pouch in rats. Gossypin was also found effective against the adjuvant and formalin induced chronic arthritis in rats 26.
Betulinic acid, a triterpene isolated from
Premnazole, an isoxazole alkaloid isolated from
Jatamansone a sesquiterpene ketone found in
Jatamansone sesquiterpene ketone found in
Central nervous system depressants phytochemicals
In a study CNS activity of swertiamarin, a secoiridoid glycoside obtained from
Lupeol isolated from stem bark extract of
Rubidianin, an anthraquinone isolated from alcoholic extract of
Withanolides, the active constituents of
Withaferin- A isolated from the roots of Withania somnifera, reduced survival of V79 cells in a dose-dependent manner. LD50 for survival was 16 microM. One-hour treatment with a non-toxic dose of 2.1 microM before irradiation significantly enhanced cell killing, giving a sensitizer enhancement ratio (SER) of 1.5 for 37% survival and 1.4 for 10% survival. SER increased with drug dose, but at higher doses the increased lethality appears to be due to two effects i.e. drug toxicity and radio sensitization. The drug induced a G2/M block, with a maximum accumulation of cells in G2-M phase at 4 h after treatment with 10.5 microM withaferin A in 1 h39.
Withaferin- A showed marked tumour-inhibitory activity when tested in vitro against cells derived from human carcinoma of nasopharynx (KB). It also acted as a mitotic poison arresting the division of cultured human larynx carcinoma cells at metaphase and in HeLa cultures similar to star -metaphase. It also produced significant retardation of the growth of Ehrlich ascites carcinoma, Sarcoma 180, Sarcoma Black (SBL), and E 0771 mammary adenocarcinoma in mice in doses of 10, 12, 15 mg./kg body-weight. Growth of Ehrlich ascites carcinoma was completely inhibited in more than half the mice, which survived for 100 days without the evidence of growth of the tumour. Withaferin-A arrested mitosis in embryonic chicken fibroblast cells40.
Withaferin-A isolated from the alcoholic extra ct of Withania somnifera showed significant antitumor and radio sensitizing effects in experimental tumors in vivo, without any noticeable systemic toxicity. Withaferin A gave a sensitizer enhancement ratio of 1.5 for in vitro cell killing of V79 Chinese hamster cells at a non-toxic concentration of approximately 2 microM41.
A free radical scavenging, anti-tumour and anti-carcinogenic activity of gossypin has been reported42. Antitumor activity of total alkaloid fraction of
In animal studies, plumbagin, napthoquinone from
Chemotherapeutically useful phytochemicals
Clausenol a carbazole alkaloid isolated from alcoholic extract of stem-bark of
In 1970 a study reported antifungal activity of Withaferin A47. Fungistatic activity of Zaluzanin-D isolated from
Glycyrrhizin, triterpenoid saponin found in
Amarogentin, a secoiridoid glycoside isolated from
Palasonin (terpene anhydride), active principle isolated
Gentistein, the active compound of
Swerchirin, xanthone from
Karanjin, a flavone showed significant hypoglycemic activity with a single dose of 0.5 mg/kg in normal rats. However it was ineffective in alloxan- induced diabetic rats57.
Apocynin isolated from
Solasodine an alkaloid of
Embelin a plant benzoquinone and active constituent of
Embelin demonstrated 100 per cent anti-implantation activity in albino rats and rabbits when given in a dose of 10mg/kg.