Total phenolic content and antioxidant activity in selected medicinal plants of Zimbabwe

Abstract

Seven commonly known medicinal plants from Zimbabwe were analysed for their antioxidant activity as well as their total phenolic content. The plant samples used in this study were Albizia amara, Elionurus muticus, Heteropyxis natalensis, Hoslundia opposita, Lippia javanica, Ocimum urticifolia and Warburgia salutaris. The plant samples were extracted using 70% ethanol. The 2,2-diphenyl-1-picrylhydrazyl radical assay was used to determine the antioxidant activity of the plant extracts, while the Folin-Ciocalteu method was used to determine the total phenolic content. The antioxidant activities of the plant extracts ranged from 95.84 ± 0.50% for E. muticus to 5.31 ± 4.47% for H. opposita. Total phenolics in the plant extract estimated as tannic acid equivalent (TAE) ranged from 0.098 ± 0.005 mg per 100 g for H. natalensis to 0.024 ± 0.006 TAE for H. opposita. There was a poor correlation (R ¼ 0.522) between total phenolic content and antioxidant activity in the plant samples. The results indicate the presence of phenolic compounds as well as significant antioxidant activity.

Effect of Solvent Type on Total Phenolic Content and Free Radical Scavenging Activity of Black Tea and Herbal Infusions

“…The highest TPC was in 50 % acetone and the least in ethyl acetate. An acetone/ methanol/water mixture solvent was also reported to extract high phenolic compounds in L. javanica (Shikanga et al (Catalan and de Lampasona 2002;Muchuweti et al 2006;Olivier et al 2010;Madzimure et al 2011). Essential oils have been extracted in L. javanica (Samie et al 2005;Viljoen et al 2005).…”

Lippia javanica (Burm.f.) Spreng.: Traditional and Commercial Uses and Phytochemical and Pharmacological Significance in the African and Indian Subcontinent

“…Multiple classes of phytochemicals including volatile and nonvolatile secondary metabolites, such as alkaloids, amino acids, flavonoids, iridoids, and triterpenes as well as several minerals, have been identified from L. javanica [1–5, 7, 13, 27, 73, 78, 81, 83–86, 88–94, 120, 123, 125–127]. Leaves, flowers, and twigs of L. javanica have a wide variety of the so-called classic nutrients, such as minerals, carbohydrates, proteins, fats, and vitamins (Table 2).…”

“…Scientific studies on L. javanica indicate that it has a wide range of pharmacological activities (Table 4), which include anticancer [140], antidiabetic [141], antimalarial [4, 49, 142], antimicrobial [2, 3, 7, 17, 73–75, 77, 83, 84, 126, 143], antioxidant [7, 10, 11, 75, 77, 125], antiplasmodial [2, 79, 80, 84, 144, 145], and pesticidal effects [1, 2, 59, 95, 120, 146–150] and cytotoxicity [2, 73, 79, 120] activities. Table 4 summarizes some of the pharmacological studies undertaken on L. javanica extracts aimed at evaluating some of the ethnomedicinal uses of the species documented throughout its distributional range (see Table 1).…”

Evaluation of the analgesic, anti-inflammatory, anti-oxidant, phytochemical and toxicological properties of the methanolic leaf extract of commercially processed Moringa oleifera in some laboratory animals

“…Tannins and saponins are also found to be effective anti-oxidants, antimicrobial and anti-carcinogenic agents [34]. Phenolics constitute one of the major groups of compounds which act as primary antioxidants [42,44]. In fact, phenolic compounds are very important plant constituents because they exhibit antioxidant activity by inactivating lipid free radicals or preventing decomposition of hydroperoxides into free radicals [45].…”