Functional characterization of khadi yeasts isolates for selection of starter cultures

4openInternationalInternational coauthor/editorYeasts play an important role in spontaneous fermentation of traditional alcoholic beverages. Our previous study revealed that a mixed-consortia of both Saccharomyces and non-Saccharomyces yeasts were responsible for fermentation of khadi, a popular, non-standardized traditional beverage with an immense potential for commercialization in Botswana. Functional characterization of isolated fermenting yeasts from mixed consortia is an indispensable step towards the selection of potential starter cultures for commercialization of khadi. In this study, we report the characterization of 13 khadi isolates for the presence of brewing-relevant phenotypes such as their fermentative capacity, ability to utilize a range of carbon sources and their ability to withstand brewing-associated stresses, as a principal step towards selection of starter cultures. Khadi isolates such as Saccharomyces cerevisiae, Saccharomycodes ludwigii and Candida ethanolica showed good brewing credentials but Lachancea fermentati emerged as the isolate with the best brewing attributes with a potential as a starter culture. However, we were then prompted to investigate the potential of L. fermentati to influence the fruity aromatic flavor, characteristic of khadi. The aroma components of 18 khadi samples were extracted using headspace solid phase micro-extraction (HS-SPME) and identified using a GC-MS. We detected esters as the majority of volatile compounds in khadi, typical of the aromatic signature of both khadi and L. fermentati associated fermentations. This work shows that L. fermentati has potential for commercial production of khadi.openMotlhanka, K.; Lebani, K.; Garcia Aloy, M.; Zhou, N.Motlhanka, K.; Lebani, K.; Garcia Aloy, M.; Zhou, N

ANALYSIS OF NUTRIENTS, TOTAL PHENOLS AND ANTIOXIDANT ACTIVITY OF FICUS SANSIBARICA WARB. FRUITS FROM EASTERN BOTSWANA

Ripe fruits of Ficussansabarica were assessed for in vitro antioxidant activity using the Free radical scavenging assay (FRSA). The scavenging activity of the fruits was evaluated spectrophotometrically as maximum fading power of1,1-Diphenyl-2-picrylhydrazyl (DPPH) at 525nm. The total phenolic content of water and methanol extracts was determined using the Folin-Ciocalteau method. The mineral composition of the fruits was analyzed using the optical emission spectrophotometer. At all tested concentrations the scavenging power of methanolic extract was higher than that of water extract. Between 100 and 200µg/ml, both extracts exhibited scavenging power of ≥85% comparable to the standard compound quercetin. The total phenolic contents of water and methanolic extracts were 3145 and 3584 mg/L GAE, respectively. The fruits contained 7.83mg/LCa,9.47mg/LMg,2.66mg/L Na, 58.1mg/L K, and 0.02mg/L P. Crude protein content as determined by the Kjeldahl method was 0.18%. These results show that these fruits are a rich source of the essential elements that have a positive effect on human health. The results support the use of these fruits as supplements for nutrient deficiencies and for combating diseases associated with oxidative damage. Keywords: mineral content; Ficussansabarica; total phenols; free radical scavenging; wild fruits

FREE RADICAL SCAVENGING ACTIVITY OF TWO MEDICINAL PLANTS USED BY DIABETIC PATIENTS IN BOTSWANA

Water extracts of Myrnthamnus flabellifolius (shoot) and Ozoroa paniculosa (roots, stem, leaves) and their combinations called “Dankatso” (equal proportion of the above plant extracts) are being used extensively in eastern Botswana traditional medicine. These plants have reputable use as antidiabetic preparations. M. flabellifolius is used to alleviate symptoms of diabetes mellitus, stroke and hypertension. O. paniculosa is used to alleviate menstrual pain and in asthma (Motlhanka, 2008). The study is part of an ongoing project to search for novel drugs from vast array of medicinal plants from Botswana, which have not been studied extensively (Motlhanka et al., 2005), The antioxidant capacity of the extracts together with their combinations was assessed spectrophotometrically using DPPH free radical scavenging assay. At 25 µg/ml the scavenging power of the extracts were as follows: M. flabellifolius alone (66%); O. paniculosa root alone (49%); O. paniculosa stem alone (81%); O. paniculosa leaf alone (79%). At the same concentration (25 µg/ml), combinations: [M. flabellifolius+O. paniculosa root] (85%); [M. flabelllifolius + O. paniculosa stem] (91%); [M. flabellifolius + O. paniculosa leaf] (91%). At 100 µg/ml and above there were no significant differences between scavenging potencies for individual extracts and their combinations (“Dankatso”). The scavenging potencies were in magnitudes of 90-91% for individual extracts and their combinations. This study suggests that the presence of antioxidant compounds in water extracts of the studied plants may be responsible for their anti-diabetic properties as advocated in traditional medicine. Acknowledgements: Traditional healers for supplying the plants. References: Motlhanka D.M et al. (2005) J. of Pharm. & Pharmacol. Vol: 57 S-7. Motlhanka, D.M (2008) Pakistan J of Biol. Sci. Vol:11 (5) 805-80

Studies on plants used in Botswana to treat infection

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Microbial and Chemical Diversity of Traditional Non-Cereal Based Alcoholic Beverages of Sub-Saharan Africa

Fermentation remains an important food preparation technique of health, cultural and economic importance throughout the world. In Sub-Saharan Africa, traditional alcoholic fermentation of cereal and non-cereal based substrates into alcoholic beverages is deeply rooted in the society. Although a multitude of traditional alcoholic beverages from cereal substrates are well researched and documented, their non-cereal based counterparts, mostly produced from indigenous, inexpensive substrates, remain less well studied. In addition, reports of health problems associated with non-cereal based alcoholic beverages produced from spontaneous fermentation are a major cause of concern. This review aims to highlight the microbiological and chemical profiles of these non-cereal based alcoholic beverages with a focus on the Sub-Saharan region. Here, we underscore the importance of the microbial repertoire and the substrates thereof in attaining aromatic complexity and a characteristic taste in these beverages. These aspects are an important starting point towards the potential commercialization of these complex aromatic non-cereal based traditional beverages

Prostaglandin E2 (PgE2) Inhibition By Crude Extracts Of Selected Medicinal Plants From Botswana

This study was undertaken to assess anti-inflammatory activity of crude extracts of Cassine transvaalensis Burtt-Davy, Clerodendrum uncinatum Schinz and Commiphora glandulosa Schinz using COX inhibition assay. Water extract of C. transvaalensis root bark (125mg/ml) exhibited a (90%) PGE2 inhibition in lipopolysaccharide (LPS) induced RAW 264.7 macrophages. This was a very good anti-inflammatory activity comparable to the control drug indomethacin (100%) at 0.4mg/ml. Chloroform extracts of C. uncinatum root (1.25mg/ml) and C. glandulosa stem resin (1.25mg/ml) exhibited good PGE2 inhibition (44% and 38%) respectively. Keywords: Anti-inflammatory activity; PGE2 inhibition; LPS induced Raw 264.7 macrophages; Botswana plants.Nigerian Journal of Natural Products and Medicine Vol. 11 2007 pp. 32-3

Free radical scavenging activity of crude extracts and 4´-O-methylepigallocatechin isolated from roots of Cassine transvaalensis Burtt-Davy from Botswana

Water and ethanol extracts of roots from Cassine transvaalensis Burtt-Davy (celastraceae) were assessed for in vitro antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay. The ethanolic extract exhibited higher free radical scavenging effect than the water extract at all tested concentrations. Above 100μg/ml, the ethanolic extract showed 80% scavenging activity, similar to control antioxidant compounds quercetin, rutin and L-ascorbic acid. The water extract reached a similar level of activity (80%) at 200μg/ml. Between 20-50μg/ml, 4'-O-methylepigallocatechin isolated by bioassay directed fractionation exhibited scavenging activity greater than that of either the ethanolic or aqueous crude extract. However, at concentrations above 50μg/ml, the scavenging activity of the ethanolic extract exceeded that of 4'-O-methyl-epigallocatechin. The results suggest that extracts from the roots of Cassine transvaalensis have strong antioxidant activity. These findings support the ethnomedical use of this plant to promote good health

Fermentative Microbes of Khadi, a Traditional Alcoholic Beverage of Botswana

Khadi is a popular traditional alcoholic beverage in rural households in Botswana. The product is produced by fermentation of ripened sun-dried Grewia flava (Malvaceae) fruits supplemented with brown table sugar. Despite its popularity, its growing consumer acceptance, its potential nutritional value, and its contribution to the socio-economic lifestyle of Botswana, the production process remains non-standardized. Non-standardized production processes lead to discrepancies in product quality and safety as well as varying shelf life. Identification of unknown fermentative microorganisms of khadi is an important step towards standardization of its brewing process for entrance into commercial markets. The aim of this study was to isolate and identify bacteria and yeasts responsible for fermentation of khadi. Yeasts and bacteria harbored in 18 khadi samples from 18 brewers in central and northern Botswana were investigated using classic culture-dependent techniques and DNA sequencing methods. Additionally, we used the same techniques to investigate the presence of bacteria and yeasts on six batches of ripened-dried G. flava fruits used for production of the sampled brews. Our results revealed that Saccharomyces cerevisiae closely related to a commercial baker’s yeast strain sold locally was the most predominant yeast species in khadi suggesting a possible non-spontaneous brewing process. However, we also detected diverse non-Saccharomyces yeasts, which are not available commercially in retail shops in Botswana. This suggests that spontaneous fermentation is partially responsible for fermentation of khadi. This study, presenting the first microbiological characterization of a prominent traditional alcoholic beverage in Botswana, is vital for development of starter cultures for the production of a consistent product towards the commercialization of khadi

Application of a sex identification technique in juvenile ostriches and its potential application in Botswana

Sexing ostrich chicks and juveniles before the dimorphous appearance of the plumage that starts at 14 months of age is proving difficult and cumbersome for Botswana farmers. This problem delays early selection of birds for breeding and trading. It also means that birds are often sold as a mixture of males and females. DNA-based sex identification provides a solution and is amenable to large-scale application. The application of the multiplex polymerase chain reaction (PCR) was used to determine the sex of 6-months old juvenile ostriches. The blood from four mature males and four mature females were used to verify the assay. The test group consisted of 19 randomly selected six-month old birds, which turned out to be 10 males and nine females. The PCR technique uses two pairs of primers. The primers SS1 and SS2 amplify a 650 base pair (bp) female-specific fragment, while the primers L014a and L014b amplify a fragment about 280 bp, from both sexes. The females were thus distinguished by amplification of two bands after agarose gel electrophoresis, and the males by one band. Following the successful application of this technique using DNA extracted from blood, further investigations have to be conducted, using DNA extracted from other body tissue samples such as feathers or skin. A scenario is envisaged whereby, during tagging of the chicks, a body tissue sample such as a blood feather could be sent to the laboratory for DNA sexing. This technique would aid farmers in identifying the sex of their birds at a young age. South African Journal of Animal Science Vol.32(3) 2002: 160-16

A novel pentacyclic triterpene glycoside from a resin of Commiphora glandulosa from Botswana

A novel ursane-type pentacyclic triterpene glycoside, 1b,2b,3b-trihydoxy-urs-12-ene-23-oic-rhamnoside was isolated from the resin of Commiphora glandulosa Schinz by bioassay guided fractionation. Crude aqueous and chloroform extracts of the resin as well as the isolated compound exhibited good in vitro antibacterial activity against gram positive bacteria (Bacillus subtilis: NCTC 10073), (Clostridium perfringens: NCTC 8237), (Staphylococcus aureus: NCIMB 9518) and also drug resistant strains (S.aureus:XU212-tetracycline resistant strain), (S. aureus SA1199B-norfloxacin resistant strain). There was no observed antimicrobial activity against gram negative bacteria (Escherichia coli: NCTC 9002), (Pseudomonas aeruginosa: NCIMB 10421), (Klebsiella aerogenes: NCTC 5055); and fungal strains (Candida albicans: NCPF 3179, Aspergillus fumigatus: NCPF 7097), Trichophyton tonsurans: NCPF 995). The structure of the isolated compound was elucidated on the basis of spectral data using13CNMR, 1H-NMR and mass spectroscopy