Some southern African plant species used to treat helminth infections in ethnoveterinary medicine have excellent antifungal activities

Abstract

BackgroundDiseases caused by microorganisms and parasites remain a major challenge globally and particularly in sub-Saharan Africa to man and livestock. Resistance to available antimicrobials and the high cost or unavailability of antimicrobials complicates matters. Many rural people use plants to treat these infections. Because some anthelmintics e.g. benzimidazoles also have good antifungal activity we examined the antifungal activity of extracts of 13 plant species used in southern Africa to treat gastrointestinal helminth infections in livestock and in man.MethodsAntifungal activity of acetone leaf extracts was determined by serial microdilution with tetrazolium violet as growth indicator against Aspergillus fumigatus, Cryptococcus neoformans and Candida albicans. These pathogens play an important role in opportunistic infections of immune compromised patients. Cytotoxicity was determined by MTT cellular assay. Therapeutic indices were calculated and selectivity for different pathogens determined. We proposed a method to calculate the relation between microbicidal and microbistatic activities. Total activities for different plant species were calculated.ResultsOn the whole, all 13 extracts had good antifungal activities with MIC values as low as 0.02 mg/mL for extracts of Clausena anisata against Aspergillus fumigatus and 0.04 mg/mL for extracts of Zanthoxylum capense, Clerodendrum glabrum, and Milletia grandis, against A. fumigatus. Clausena anisata extracts had the lowest cytotoxicity (LC50) of 0.17 mg/mL, a reasonable therapeutic index (2.65) against A. fumigatus. It also had selective activity against A. fumigatus, an overall fungicidal activity of 98% and a total activity of 3395 mL/g against A. fumigatus. This means that 1 g of acetone leaf extract can be diluted to 3.4 litres and it would still inhibit the growth. Clerodendrum glabrum, Zanthoxylum capense and Milletia grandis extracts also yielded promising results.ConclusionsSome plant extracts used for treatment of parasitic infections also have good antifungal activity. Because it is much easier to isolate antifungal compounds by bioassay guided fractionation, this approach may facilitate the isolation of anthelmintic compounds from active plant extracts. The viability of this approach can be tested by isolating the antifungal compounds and then determining its anthelmintic activity. Some of these plant extracts may also be useful in combating fungal infections.

The antibacterial activity, antioxidant activity and selectivity index of leaf extracts of thirteen South African tree species used in ethnoveterinary medicine to treat helminth infections

“…Previously, report on the anthelmintic [6] and antifungal activity [7] of acetone extracts of these plant species have shown varied degree of activity. The most promising plant extracts against egg hatching and larval development of Haemonchus contortus were H. trifoliata, M. lanceolata and L. sericea .…”

Antifungal Activity of Decyl Gallate against Several Species of Pathogenic Fungi

“…The IC 50 values of both cell lines were calculated in relation to G1 molecule and the best antifungal activity of alkyl gallate is the G14. This value represents the concentration required for 50% cell death (i.e., the concentration of each alkyl gallate that results in 50% absorbance reduction compared with untreated cells, termed the IC 50 ) [ 17 ]. The selective index (SI) was calculated to both cells lines, which is defined as the ratio of the measured IC 50 in the two cell lines to the MIC of the tested alkyl gallate (i.e., SI = IC 50 /MIC).…”

Rapid Screening using GIBEX Screens-to-nature System of Ethnomedicinal Plants from Ngong Forest, Kenya for Potency against Infectious Diseases and Antioxidant Activities: A Qualitative Study

“…[102][103][104] Leaves Used for the treatment of tuberculosis, back wounds, spinal weakness. 105 Has hypoglycaemic, 125 is an inhibitor of HIV-1 and HIV-2 replication, 119 antispasmolytlc, 117 antibacterial, 121,126 antimicrobial, [127][128][129] behavioral and anticonvulsant, [130][131] mollucidcidal, 118 insecticidal effect, [132][133][134][135] larvicidal, [136][137] antiplasmodial and analgesic, 138 antifungal activities, [139][140] in vivo antimalarial and acute toxicity properties, 141 antibacterial and antioxidant, 124,[142][143] antitumor, 144 antihyperglycaemic, 145 antifeedant 146 and cytotoxic activities. 126 Monoterpenoid furanocoumarin lactones, 117 quinolone and carbazole alkaloids, γ-lactone carbazoles, [147][148][149][150] acridone alkaloids, 124 volatile constituents, 151 substituted coumarins, [152][153][154][155][156]…”