The use of medicinal plants in South Africa is cultural. Withania somnifera is one of the medicinal plants used to treat various ailments in the country. The plant species has been used by traditional medicine practitioners to treat inflammation and painful conditions like rheumatism. It is also known to be used as a sedative and hypnotic drug. Despite the claims, there is no information in literature to corroborate the therapeutic success of Withania somnifera in the treatment of inflammation and insomnia. The study, therefore, investigated the anti-inflammatory and central nervous system depressant activities of the leaf aqueous extract of the plant species in mice and rats. Fresh leaves of W. somnifera were collected from Kirstenbosch Botanical Gardens, South Africa, authenticated by a taxonomist and a voucher specimen (UWC 005) deposited in the University’s Herbarium. Leaf aqueous extract was prepared using standard extraction methods. The carrageenan-induced rat paw oedema test was used to determine the anti-inflammatory effects while pentobarbitone-induced sleep and locomotor activity tests were used to evaluate the sedative effect of the plant species. Phytochemical qualitative analysis, acute toxicity and HPLC studies of the plant species were also carried out using standard methods. The phytochemical qualitative analysis carried out on the dried powdered leaves of W. somnifera showed the presence of saponins, tannins and triterpene steroids. Leaf aqueous extract of W. somnifera (100-200 mg/kg IP) significantly prolonged pentobarbitone (40 mg/kg, i.p.)-induced sleep in mice in a dose dependant manner. Diazepam (0.5 mg/kg, i.p.) significantly prolonged pentobarbitone (40 mg/kg, i.p.)-induced sleep in mice. The doses of 100 and 200 mg/kg (i.p.) of the plant species and 0.5 mg/kg (i.p.) of diazepam significantly reduced the locomotor activity of mice. Leaf aqueous extract of the plant species (50-200 mg/kg, i.p.) significantly reduced the oedema produced by carrageenan (1%) in rats over 90 min period of testing. Indomethacin (20 mg/kg, i.p.) significantly reduced carrageenan (1%)-induced oedema in rats over 120 min period of testing. The LD50 value obtained for the leaf aqueous extract of the plant species following inter-peritoneal injection was 1,600 mg/kg while that following oral administration was probably over 4,000 mg/kg. The HPLC finger-print of the aqueous extract showed distinct peaks at the following retention times 2.977, 3.594, 4.154, 4.406, 4.660 and 15.267 min. The results obtained show that leaf aqueous extract of W. somnifera has both sedative and anti-inflammatory effects.

Author Name: George Jimboyeka Amabeoku, Oluchi Nneka Mbamalu, Munira Ismail, Nabeel Dudhia, Nadeem Noordien, Zukiswa Mabuya and Oatlhostse Kakutsi

URL: View PDF

Keywords: Withania somnifera, solanaceae, leaf aqueous extract, anti-inflammatory activity, Pentobarbitone-induced sleep test, locomotor activity, phytochemical analysis, acute toxicity, HPLC study, mice, rats.

ISSN: 2328-2150

EISSN:

EOI/DOI: 10.17265/2328-2150/2015.10.004

Add Citation Views: 1

---