The medicinal properties of ipomoea oblongata E.Mey. ex Choisy

Abstract

Traditional medicine has been known by mankind since ancient times as a healthcare system. All cultures have used herbs throughout history and it was an integral part of the development of modern civilization. Primitive man observed and appreciated the great diversity of plants available to him. Plants provided food, clothes, shelter and medicine and still play a vital role in rural villages of South Africa. The medicinal uses of plants and animals have been developed through trial and error. Herbal plants produce and contain a wide variety of chemical substances that act upon the body’s immune system. The medicinal properties of Ipomoea oblongata (E.Mey.ex Choisy) in this study was to determine the phytochemical content, antioxidant, anti-cancer and anti-diabetic properties of I. oblongata (Mothokho), a medicinal plant used by traditional medical practitioners of Thaba-Nchu in the Free State. The study was carried out in order to validate the ethnomedicinal claims made by the traditional medical practitioners and to evaluate the plant’s potential as a novel therapeutic agent. Twelve traditional medical practitioners of the Kopanang Dingaka Association were interviewed on the knowledge and use of I. oblongata (Mothokho). The phytochemical constituents of the plant were determined using standard screening methods. Testing for antioxidant properties (free radical scavenging activity) was carried out by means of the 2, 2- diphenylpicrylhydrazyl (DPPH) assays. The Sulforhodamine B assay was used to screen for anti-cancer activity in breast (MCF7), colon (HCT116) and prostate (PC3) cancer cell lines. Glucose uptake in C2C12 muscle cells was used to evaluate the anti- iii diabetic potential of I. oblongata. Methanol extract was fractionated using Ultra-Pure Liquid Chromatography (UPLC) to identify active compounds. The traditional medical practitioners cited the plant roots as the main ingredient in the treatment of respiratory infections, sexually transmitted infections, postnatal womb treatments, inflammation, arthritis, wounds and cancer. The methanol extract of I. oblongata showed remarkable (99.03%, 98.39, 71.31%) antioxidant potential in all triplicates tested which explains its use in oxidative stress-related diseases such as arthritis and cancer. Phytochemical tests showed the presence of carbohydrates, glycosides, steroids, terpenoids, alkaloids, flavonoids and tannins. However, the extracts were inactive against the cancer cell lines used. Glucose uptake by the C2C12 muscle cells was increased by over 150% and was comparable to that of insulin and metformin, suggesting good anti-diabetic activity. Predicted compounds found were dihydroquercetin pentaacetate, actinorhodin and actinorhodine, using Chemspider analysis. These are possible compounds that could be found in the Ipomoea oblongata extracts when using nuclear magnetic resonance (NMR) to determine the structure and names of the active compounds. Ethnobotanical uses of Ipomoea oblongata were found to have a link with other ethnobotanical studies to capture the indigenous knowledge, culture and therapeutic uses. The phytochemical results of Ipomoea oblongata can contribute to the knowledge of new drug development as indicated by literature (Harbone; 1973, Soforowa, 1993; De et al., 2010) that plants contain phytochemical contents and phenolic compounds that are valuable as medicinal properties. Methanolic extract of Ipomoea oblongata presented high levels of antioxidant activity respectively, which can become a potential iv antimicrobial agent and remedy oxidative stress related diseases. The anticancer properties were inactive and the cytotoxicity levels were found to below in I. oblongata. Low levels of cytotoxicity allow medicinal plants to be consumed by humans with fewer side effects however doses must be standardized. High levels of glucose uptake in muscle cells were indicated from the aqueous extract of Ipomoea oblongata, therefore showing great potential as an antidiabetic agent. Many medicinal plants have been validated as antidiabetic therapeutic agents in South Africa and the world. New treatment of cancer, diabetes, bacterial and viral infections is required from natural products that are cost effective with minimal side effects that can be used in health care systems. There is a correlation between the medicinal properties found in I. oblongata and the ethnomedicinal uses cited by the traditional medical practitioners. The plant I. oblongata has six ethno-pharmaceutical uses. I. oblongata is a good source of anti-diabetic and antioxidant agents that can be developed further. However the plant is not a good source of anticancer properties. Future research will be into the isolation and identification of the active compounds.