Antimicrobial and acetylcholinesterase inhibitory activities of Buddleja salviifolia (L.) Lam. leaf extracts and isolated compounds.

ETHNOPHARMACOLOGICAL RELEVANCE: Buddleja salviifolia leaves are used for the treatment of eye infections and neurodegenerative conditions by various tribes in South Africa. AIM OF STUDY: This study was designed to isolate the phenolic constituents from the leaf extracts of Buddleja salviifolia and evaluate their antimicrobial and acetylcholinesterase (AChE) activities. MATERIAL AND METHODS: Three phenolic compounds were isolated from the ethyl acetate fraction of a 20% aqueous methanol leaf extract of Buddleja salviifolia using Sephadex LH-20 and silica gel columns. Structure elucidation of the isolated compounds was carried out using spectroscopic techniques: mass spectrometry (ESI-TOF-MS) and NMR (1D and 2D). The extracts and isolated compounds were evaluated for antimicrobial and acetylcholinesterase activities using the microdilution technique. The bacteria used for the antimicrobial assays were Gram-positive Bacillus subtilis and Staphylococcus aureus and Gram-negative Escherichia coli and Klebsiella pneumoniae. RESULTS: The isolated compounds were characterized as: 4'-hydroxyphenyl ethyl vanillate (1) a new natural product, acteoside (2) and quercetin (3). The crude extract, fractions and the isolated compounds from the leaves of the plant exhibited a broad spectrum of antibacterial activity. The EtOAc fraction exhibited good activity against Bacillus subtilis and Staphylococcus aureus with MIC values ranging from 780.0 to 390.0 µg/mL. Isolated compound 2 exhibited good activity against Staphylococcus aureus with an MIC value of 62.5 µg/mL. The hexane and DCM fractions of leaves showed the best activity against Candida albicans with MIC and MFC values of 390.0 µg/mL. In the AChE inhibitory test, among the tested extracts, the hexane fraction was the most potent with an IC50 value of 107.4 µg/mL, whereas for the isolated compounds, it was compound (3) (quercetin) with an IC50 value of 66.8 µg/mL. CONCLUSIONS: Activities demonstrated by the extracts and isolated compounds support the ethnopharmacological use of Buddleja salviifolia against eye infections and neurodegenerative diseases.

Effect of administration of aqueous extract of hippobromus pauciflorus leaves in male Wistar rats.

The effect of administration of aqueous extract of Hippobromus pauciflorus (L.f.) Radlk (Sapindaceae) leaves at 50, 100 and 200 mg/kg body weight for 14 days on some biochemical parameters in male Wistar rats was investigated. The extract at all the doses tested did not significantly (P>0.05) alter the levels of white blood cells, red blood cells, mean corpuscular volume, platelets, neutrophils, monocytes, lymphocytes and large unstained cells. While the levels of haemoglobin, packed cell volume and basophils increased significantly (P<0.05) at specific doses, the mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration and eosinophils decreased significantly (P<0.05). Again, the extract did not significantly (P<0.05) alter the computed liver- and kidney-body weight ratios, sodium, chloride and total protein, though, the levels of potassium, inorganic phosphorus, globulin, urea, total and conjugated bilirubin increased significantly (P<0.05) at certain doses. In contrast, the levels of albumin and creatinine also decreased significantly (P<0.05) at specific doses. While the activities of alkaline phosphatase, gamma glutamyl transferase and alanine aminotransferase remained significantly (P<0.05) unaltered in the serum, aspartate aminotransferase activity increased only at 200 mg/kg body weight. The atherogenic index as well as the concentrations of cholesterol, high- and low-density lipoprotein cholesterol in the serum of the animals were not significantly (P>0.05) altered. However, the extract significantly (P<0.05) increased the concentration of triacylglycerol. The results suggest that the extract has mild and dose specific haemato-, hepato- and nephrotoxic effects and may not be completely safe as oral remedy at the doses investigated.

The study on foliar micromorphology of Hippobromus pauciflorus using scanning electron microscope.

Foliar micromorphology of Hippobromus pauciflorus (L.f.) Radlk (Sapindaceae) was investigated by scanning electron microscope examination. The leaves were characterized by anisocytic stomata which were found only on the abaxial surface. The leaves have long unicellular non-glandular trichomes which were distributed over the mid rib and densely populated at the edges of the upper and lower surfaces. Crystal deposits were also observed on the abaxial surface of the leaves. Energy dispersive X-ray spectroscopy SEM of the crystals showed predominant mineral components of Na, Al, Si, K and Ca ions. These micro (Si, Na and Al) and macro (K and Ca) elements are very essential to plant growth. Their presence in the trichomes could contribute to the mechanical stability of the leaf appendages.

An ethnobotanical study of plants used for the treatment of eye infections in the Eastern Cape Province, South Africa.

Information on medicinal plants, used by the people of the Eastern Cape for the treatment of eye infections, was collected through questionnaires which were administered to herbalists, traditional healers and rural dwellers. The information collected revealed 12 plant species. These plants belong to 9 families, of which Sapindaceae was the most prominent. The leaves were reported to be the most used part of the plants, constituting 75% of herbal preparations. This was followed by bark and roots which constituted 25%. Generally, the plant parts are crushed and the sap squeezed directly into the infected eyes. In few cases, the material is mixed with water and boiled; after cooling, the extract is applied to the infected eyes. Hippobromus pauciflorus was the most commonly used plant species for the treatment of eye infections in the province. Majority of the plants used have been reported in literature to possess some other pharmacological activities.