Florence O. Jimoh

Antibacterial and antioxidant properties of the methanol extracts of the leaves and stems of Calpurnia aurea

BackgroundIn South Africa, Calpurnia aurea (Ait.) Benth is used to destroy lice and to relieve itches, to destroy maggots and to treat allergic rashes, particularly those caused by caterpillars. Antioxidants play an important role protecting against damage by reactive oxygen species. Plants containing flavonoids have been reported to possess strong antioxidant properties.MethodsThe antibacterial, antioxidant activities and phenolic contents of the methanol extracts of the leaves and stems of Calpurnia aurea were evaluated using in vitro standard methods. Spectrophotometry was the basis for the determinations of total phenol, total flavonoids, flavonols, and proanthocyanidins. Tannins, quercetin and catechin equivalents were used for these parameters. The antioxidant activities of the stem extract of Calpurnia aurea were determined by ABTS, DPPH, and ferrous reducing antioxidant property (FRAP) methods. Laboratory isolates of 10 bacteria species which included five Gram-positive and five Gram-negative strains were used to assay for antibacterial activity of this plant.ResultsThe results from this study showed that the antioxidant activities of the stem extract of Calpurnia aurea as determined by the total phenol, flavonoids, and FRAP methods were higher than that of the leaves. On the other hand, the leaf extract of the plant has higher level of total flavonols and proanthocyanidins. The leaf extract also has higher radical scavenging activity as shown in 1, 1-Diphenyl-2-picrylhydrazyl (DPPH), and 2,2¿-azinobis-3- ethylbenzothiazoline-6-sulfonic acid (ABTS) assay. The leaf extract showed activity against seven of the bacterial organisms.ConclusionThe results from this study indicate that the leaves and stem extracts of Calpurnia aurea possess antioxidant properties and could serve as free radical inhibitors or scavenger or, acting possibly as primary antioxidants. Although, the antibacterial properties of Calpurnia aurea are not as effective as the standard drugs- Chloramphenicol and Streptomycin, they still possess some activity against bacterial strains used in this study. Calpurnia aurea may therefore be a good candidate for functional foods as well as pharmaceutical plant-based products.

Assessment of the medicinal potentials of the methanol extracts of the leaves and stems of Buddleja saligna

BackgroundBuddleja saligna Willd (Loganiaceae) is a small to medium-sized evergreen tree; trunk short, often gnarled and crooked; crown dense, rounded or domed-shaped; foliage greyish green. The wild olives are traditionally used to lower blood pressures in many parts of the world. In southern Africa, bark and leaf decoctions are used to treat colic, coughs, colds, sore eyes, urinary problems and as purgatives.MethodsThe antibacterial, antioxidant activities and phenolic contents of the methanol extracts of the leaves and stems of Buddleja saligna were evaluated using in vitro standard methods. Spectrophotometry was the basis for the determinations of total phenol, total flavonoids, flavonols, and proanthocyanidins. Tannins, quercetin and catechin equivalents were used for these parameters. The antioxidant activities of the leaves and stem extracts of Buddleja saligna were determined by ABTS, DPPH, and ferrous reducing antioxidant property (FRAP) methods. Laboratory isolates of 10 bacteria species which included five Gram-positive and five Gram-negative strains were used to assay for antibacterial activity of this plant.ResultsThe antioxidant activities of the leaves as determined by the ABTS and DPPH were similar to that of the stem. The flavonoids and the flavonols contents of the leaves were higher than that of the stem but the total phenols, proanthocyanidins and FRAP activities were higher in the methanol extracts of the stem. The extracts did show activity against both Gram-positive and Gram-negative bacteria. For instance, while the methanol extract of the leaves showed good activities on all the organisms except Serratia marcescens and Pseudomonas aeruginosa at MICs of between 2.5 and 5.0 mg/ml, the extract of the stem only showed activities on Bacillus cereus, Streptococcus pyrogens and Pseudomonas aeruginosa at the same concentration.ConclusionThe results from this study indicate that the leaves and stem extracts of Buddleja saligna possess antioxidant properties and could serve as free radical inhibitors or scavenger or, acting possibly as primary antioxidants. Although, the antibacterial properties of Buddleja saligna are not as effective as the standard drugs-Chloramphenicol and Streptomycin, they still possess some activity against bacterial strains used in this study. Buddleja saligna may therefore be a good candidate for functional foods as well as pharmaceutical plant-based products.

Evaluation of the medicinal potentials of the methanol extracts of the leaves and stems of Halleria lucida.

The medicinal potentials of the methanol extracts of the leaves and stems of Halleria lucida (Scrophulariaceae) were evaluated by assessing their antibacterial and antioxidant properties in vitro using standard procedures. The antioxidant activities of methanol extract of the leaves as determined by the ABTS, DPPH, proanthocyanidins and total flavonoids were higher than that of the stem. On the other hand, the total phenols, the flavonoids and the FRAP contents of the stem were higher than that of the leaves. The extracts however showed poor activity against both Gram-positive and Gram-negative bacteria. The methanol extract of the stem showed activities against Bacillus cereus and Staphylococcus epidermidis at MIC of 1.0 mg/ml. The methanol extract of the leaves did not show activity against any of the organisms used in this study. This study has to some extent validated the medicinal potential of the leaves and stems of H. lucida.

COMPARISON OF THE NUTRITIONAL VALUE AND BIOLOGICAL ACTIVITIES OF THE ACETONE, METHANOL AND WATER EXTRACTS OF THE LEAVES OF SOLANUM NIGRUM AND LEONOTIS LEONORUS

The nutritional, phytochemical, antioxidant and antibacterial activities of the acetone, methanol and water extracts of the leaves of Solanum nigrum and Leonotis leonorus were investigated using standard analytical methods in order to assess the numerous potential of the leaves of these plants. The proximate analysis showed the that the leaves of the two plants were rich in moisture content, ash content, crude protein, crude lipid, crude fibre and carbohydrate. Elemental analysis in mg/100g (DW) indicated that the leaves contained sodium, potassium, calcium, magnesium, iron, zinc, phosphorus, copper, manganese, and nitrogen. The chemical composition in mg/100g (DW) for alkaloid, saponins, and phytate were moderate. The plants were also rich in polyphenols and had good antioxidant activities. The different extracts of the plants had activities against some of the organisms used in this study. Comparing the nutrient and chemical constituents with recommended dietary allowance (RDA) values, the results reveal that the leaves contain an appreciable amount of nutrients, minerals, and phytochemicals and low levels of toxicants.

Polyphenolic Contents and Biological Activities of Rumex ecklonianus

Abstract Rumex ecklonianus. Meissner (Polygonaceae) is a wild South African herb whose leaves are edible when young. It is mildly purgative and is used in the treatment of chlorosis and anemia. The polyphenolic content and antioxidant and antibacterial activity of the acetone, methanol, and water extracts were determined in this study. The concentrations of the different classes of phenolic compounds were higher in the acetone and methanol extracts when compared with the water extracts; this also correlates highly with the total phenolic content. Antioxidant activities of acetone and methanol extracts as assessed by three established in vitro. methods, namely, 2,2-azinobis.-(3-ethyl benzothiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) methods were comparable with that of butylated hydroxyl toluene. The extracts showed significant activity against both Gram-positive and Gram-negative bacteria. The strongest antibacterial activity was found in the acetone extract, whose activity was pronounced on 7 of the 10 bacterial strains used, with a MIC value of 2.0 mg/mL. None of the extracts, however, inhibited Staphylococcus epidermidis. or Salmonella pooni.. The data obtained in this study suggest that R. ecklonianus. may be a good candidate for functional foods as well as pharmaceutical plant-based products. This is the first report on the biological activity of R. ecklonianus..

Medicinal Potential of the Root of Arctotis arctotoides

Abstract The antioxidant and antimicrobial activity of the acetone, methanol, and water extracts from the root of Arctotis arctotoides. (L.f.) O. Hoffm (Asteraceae) were assessed in an effort to validate the medicinal potential of the subterranean part of the herb. The antioxidant activities of acetone and methanol extracts as determined by the ABTS, DPPH, and FRAP methods were higher than that of water extracts. The extracts showed significant activity against both Gram-positive and Gram-negative bacteria. The strongest activity was found in the acetone extract on Bacillus cereus., Staphylococcus aureus., Micrococcus kristinae., and Streptococcus pyrogens. with an MIC of 0.1 mg/mL. Although not completely fungicidal, these extracts showed significant growth inhibition against all the fungi tested. Antioxidant and antimicrobial activities of the extracts were strongly correlated with total phenols and to a lesser extent with their flavonoids and proanthocyanidins contents. This study has validated the medicinal potential of the underground part of A. arctotoides..