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Prof
Zharare, Godfrey Elijah
Department: Agriculture
Research Interest(s): Extraction and Physiochemical properties of essential and Vegetable oils, Botany and genetics of oil-bearing plants, Cosmeceutical, pharmaceatical utilization od esseantial, and vegetable oils.
Active Research Project(s): Bio-refinery of Strychnos madagascariensis fruit (Ikwakwa).
Validation of Ikwaflakes and Kwafee as nutraceutical foods for managing Hyperlipidaemia, Diabetes, and Hypertension.
Optimization of Oil Extraction from Strychnos madagascariensis and Technology Transfer.
Variation in morphology, Proximate components, and Genetic attributes of Strychic spinosa genotypes.
Morphological variation, Genetics, Volatile oil yield in Laggera alata, and Laggera crispata species in Northern KwaZulu-Natal, South Africa.
Active Community Engagement: UNIZULU King Cetshwayo District Content Workshop for grade 10-12 economics educators (2021).
Biography: Prof G.E. Zharare is Professor under Agriculture Department in the Faculty of Science, Agriculture and Engineering at the University of Zululand. He is Plant Scientist with specialization in Agronomy and plant physiology. Prof Zharare is an NRF C3 rated researcher who has published numerous peer-reviewed articles. He has supervised many postgraduate students to completion in plant sciences. He also acts as a reviewer for a number of international journals on plant sciences.
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- Strychnos madagascariensis also known as black monkey orange is found in tropical and subtropical Africa including South Africa, Lesotho, Zimbabwe, and Swaziland. The fruit is consumed traditionally as food in the northern coastal region of Kwazulu-Natal in South Africa and the Southern part of Zimbabwe. This study investigated the nutritional, anti-nutritional composition, and cytotoxicity of S. madagascariensis ripe fruit. Fruits were randomly selected, and the parameters of each experiment were measured in triplicates. The seed coat and fruit pulp were analysed for proximate, mineral and anti-nutrients (phytic and oxalic acid) composition using standard protocols. The cytotoxic effect of methanolic extracts from the fruit parts of S. madagascariensis was tested on human embryonic kidney (HEK293) and cervical cancer (HeLa) cell lines using the MTT [3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide] cell proliferation assay. The fruit pulp’s moisture (6%), ash (11%), protein (5%), fat (1%), fibre (12%), and carbohydrate (12%) contents were significantly different (P<0.05) from the compositions of the fruit pulp (5% moisture, 5% ash, 4% protein, 33% fat, 8% fibre and 11% carbohydrate). The minerals analysed were significantly (P<0.05) higher in the fruit pulp compared to the seed coat (testa). The fruit's seed coat and fruit pulp's methanolic extracts did not show any significant toxicity in the HEK293 cell line. The seed coat's methanolic extract exhibited moderate toxicity in the HeLa cell line. The methanolic extracts from both fruit parts showed a dose-dependent effect in HEK293 and HeLa cell lines. The results of the cytotoxicity analysis revealed the safe nature of the fruit pulp while caution needs to be taken when consuming the seed coat. The seed coat contained 1.39±0.01% phytic acid, but oxalic acid and phytic acid were not detected in the fruit pulp. This study suggests that the fruit parts could serve as a source of potassium, magnesium, and nitrogen, but poor sources of protein, carbohydrates, and fat (pulp).
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- Strychnos spinosa Lam., commonly known as green monkey orange, is a highly valued indigenous fruit tree in South Africa with potential for domestication and commercialization. However, no study has reported on the molecular diversity of Strychnos spinosa morphotypes. Therefore, this study aimed to determine genetic variation among 32 Strychnos spinosa morphotypes using simple sequence repeat (SSR) markers. Fourteen amplified SSR markers produced 159 alleles, with a mean of 5.68 per locus. The polymorphic information content (PIC) values ranged from 0.22 (Ssp_1) to 0.84 (Ssp_6). Morphotypes were clustered in a biplot based on their genetic distances. The dendrogram chiefly discriminated morphotypes according to variation of pericarp texture. The population structure had the highest delta value K = 3, thus the 32 morphotypes were divided into three subpopulations based on the Bayesian approach. The affinities produced by the population structure agreed with the genetic distance of closely related morphotypes. This study is the first to report on SSR marker development and their successful use for genetic diversity and population structure studies of Strychnos spinosa. It provides insights into the molecular characterisation of Strychnos spinosa. This can lead to breeding programs and crop improvement programs, particularly in varietal developmental programs, which can contribute to alleviating food security challenge.
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- The majority of rural communities in South Africa are characterised by insufficient nutrition and food insecurity at the household level. Due to a lack of information about indigenous fruit trees and their use, food-insecure households are missing out on the nutrition that these fruits provide. Strychnos spinosa Lam. (monkey orange; umHlala) has been identified as one of southern Africa’s top priority fruit species for domestication. However, indigenous information on S. spinosa usage and morphological diversity is still lacking. Indigenous knowledge of species characteristics might be a good place to start when attempting to understand variations in key phenotypic traits. Information on the use and morphological variation of S. spinosa was collected from participants of 100 randomly selected homesteads. Participants were interviewed using a structured questionnaire. The results indicate that S. spinosa is a multi-purpose tree with numerous uses. Most respondents (97%) mentioned that they use it for fermented maize meal (umBhantshi); and others mentioned fermented porridge (amaHewu); alcohol; fruit; juice; jam; homestead protection; snakebite; firewood; food allergy; livestock increase; and only 7% mentioned for stomachache. Morphological variation was observed in leaf colour and shape, fruit rind colour, size, rind texture, pulp colour, pulp texture, and taste. However, the most mentioned variety featured green (78%), rounded leaves (78%) and green (39%), large (46%), smooth-textured rind (73%) fruits that had brown pulp (54%) and tasted sweet (58%). Understanding local knowledge systems and preferences can thus inform the selection of ethno-varieties that hold importance to local people and the potential to improve livelihoods in externally led domestication and development programs.
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- 2022| Scientific Research ...Mineral sands mining is worldwide an environmental issue and also at the Hillendale mine in KwaZulu-Natal, South Africa. The post-mined soil is to be rehabilitated to sugarcane cropping. One of the concerns with the post-mined soil which is reconstituted with a 70:30 mixture of sand: slimes (silt-plus-clay fraction), is its low phosphorus (P) status, which could be limiting for optimum sugarcane production. A field experiment was conducted on a reconstituted soil at Hillendale to establish the availability of either residual or applied inorganic P to the plant and first ratoon sugarcane crop. Four treatments were evaluated including those where P fertilizer was omitted, applied at half the recommended rate or introduced equal to the recommended rate according to chemical analysis of the soil. In the fourth treatment, no fertilizer was applied at all, whereas nitrogen (N) and potassium (K) were added at recommended rates in the first three treatments. Phosphorus application had a significant effect on sugarcane fractional light interception and aboveground biomass yield of the plant and first ratoon crops, and stalk length and diameter of the first ratoon crop. Pol, brix, purity and fibre content and tiller number were not affected by P application. The application of P increased the foliar N, P, K, calcium (Ca), magnesium (Mg) and sulphur (S) contents of both crops. However, foliar N, P and K were deficient in the first ratoon crop even in the case where fertilizer was applied at the recommended rates, which could have been because of waterlogging. The possible effect of waterlogging on P uptake needs to be addressed in future studies in this reconstituted soil.
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- Plants encounter several biotic and abiotic stresses, usually in combination. This results in major economic losses in agriculture and forestry every year. Climate change aggravates the adverse effects of combined stresses and increases such losses. Trees suffer even more from the recurrence of biotic and abiotic stress combinations owing to their long lifecycle. Despite the effort to study the damage from individual stress factors, less attention has been given to the effect of the complex interactions between multiple biotic and abiotic stresses. In this review, we assess the importance, impact, and mitigation strategies of climate change driven interactions between biotic and abiotic stresses in forestry. The ecological and economic importance of biotic and abiotic stresses under different combinations is highlighted by their contribution to the decline of the global forest area through their direct and indirect roles in forest loss and to the decline of biodiversity resulting from local extinction of endangered species of trees, emission of biogenic volatile organic compounds, and reduction in the productivity and quality of forest products and services. The abiotic stress factors such as high temperature and drought increase forest disease and insect pest outbreaks, decrease the growth of trees, and cause tree mortality. Reports of massive tree mortality events caused by “hotter droughts” are increasing all over the world, affecting several genera of trees including some of the most important genera in plantation forests, such as Pine, Poplar, and Eucalyptus. While the biotic stress factors such as insect pests, pathogens, and parasitic plants have been reported to be associated with many of these mortality events, a considerable number of the reports have not taken into account the contribution of such biotic factors. The available mitigation strategies also tend to undermine the interactive effect under combined stresses. Thus, this discussion centers on mitigation strategies based on research and innovation, which build on models previously used to curb individual stresses.
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- Reactive oxygen species are implicated in multiple pathological conditions including erectile dysfunction. This study evaluated the in vitro and in vivo antioxidant potential of the methanolic extracts of Inula glomerata and Salacia kraussii. The plant materials were pulverized and extracted with methanol. The phytochemical analysis, ability of the crude extracts to scavenge free radicals (ABTS, DPPH, NO.) in vitro as well as the total phenolic and flavonoid contents was investigated. In vivo, antioxidant potentials of the crude extracts (50/250 mg/kg body weight) were determined in an erectile dysfunction rat model. The phytochemical analysis revealed that both plants contain flavonoids, tannins, terpenoids, and alkaloids. The crude extracts at varying degree of efficiency, scavenged ABTS and DPPH radicals. The crude extracts at low concentrations (50 mg/kg bw) significantly (p< 0.05) diminished the level of malondialdehyde, augmented catalase activities and elevated glutathione levels. However, SOD activities were significantly boosted in a dose-dependent manner by the crude extracts. Therefore, I. glomerata and S. kraussii possess antioxidant properties, hence, can serve as a therapeutic modality in the treatment of oxidative stress-induced erectile dysfunction.
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- Strychnos spinosa Lam. of the Loganiaceae family is associated with versatility, poverty eradication, and rural economic development. However, the morphological diversity of S. spinosa is not well documented. This limits efforts toward its improvement and commercial exploitation. This study aimed to characterize the variability, vegetative and reproductive traits, and heritability of S. spinosa morphotypes at Bonamanzi Game Reserve. The majority of the morphotypes had green, rough, round immature fruits with dark green, elongated, open fully developed leaves. Fruits varied between roundish and pyriform shape as well as green and purple colour. Positive correlation was mainly seen between fruit and seed traits. Principal component analysis indicated fruit and seed traits as major discriminating factors for morphotypes, followed by leaf size and seed thickness. A dendrogram primarily grouped morphotypes according to fruit texture. Genotypic variance and genotypic coefficient of variation were higher than environmental variance and environmental coefficient variation in reproductive traits of S. spinosa. A rough pericarp texture and purple tinge on the immature leaves of some morphotypes was recorded for the first time. Differences in morphological features across S. spinosa morphotypes indicate a high level of diversity that could be utilized by breeders to generate new cultivars. This first report on variability and heritability among S. spinosa morphotypes forms the basis of available germplasm essential for future breeding programs.
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- 2022| ElsevierA study was undertaken to quantify screw press-extractable oil in the seed coat of Strychnos madagascariensis (Poir.) fruits harvested from trees in the northern coastal plain of KwaZulu-Natal province of South Africa and to determine the physiochemical properties and fatty acid composition of the oil. The seed coat constituted 19.36% of the dry fruit biomass and contained w/w 42% oil. Thus, the oil yield of the dried fruit was approx. 8.13%. Monounsaturated oleic acid accounted for between ca.70–73% of the total fatty acids in the Strychnos oil. Palmitic acid was present in amounts ranging between 15.05 and 16.27%. Also present, but in smaller amounts were cis linoleic acid (5.76–6.03%), stearic acid (1.64–4.65%), n3 linolenic acid (1.26–1.90%), and palmitoleic acid (1.10–1.65%). The oil contained trace amounts of arachidic acid (0.45–0.54%) and eicosenoic acid (approx.0.325%). Vitamin E was present in appreciable amounts, mostly in the form of α-tocopherol (approx. 5.8–14.4 mg/100 g oil) and β-tocotrienol (approx. 8.1–15.6 mg/100 g oil) homologues. The downside was that the oil had high acid values (161–181.32 mg KOH/g) and free fatty acid content (66–81 g oleic acid/100 g oil). There were 141 volatile compounds detected in the Strychnos oil, the most dominant of which were butyl-butyrate (20%), butyl hexanoate (8.2%) and glycerol (6.1–6.7%). Overall, the results indicate that Strychnos madagascariensis has potential as a source of vegetable oil.
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- Inula glomerata Oliv. & Hiern and Salacia kraussii (Harv.) Harv are medicinal plants used by traditional healers in remote areas of Mbazwana, Northern KwaZulu-Natal, South Africa for ameliorating male sexual disorders including erectile dysfunction (ED), low sperm count and early ejaculation. The study aimed at determining the ameliorative effect of the methanolic crude extracts of Inula glomerata (I. glomerata) and Salacia kraussii (S. kraussii) on butanol-induced erectile dysfunction in Sprague Dawley rats. The crude extract was prepared by maceration using methanol. Animal study was conducted whereby thirty-five male Sprague Dawley rats were divided into seven experimental groups: normal group, n-but (10 mg/kg), n-but+ Ig (50 and 250 mg/kg), n-but+ Sk (50 and 250 mg/kg) and n-but+ Cialis (5mg/kg). The experiment lasted for 28 days, after which various biochemical assays (acetylcholinesterase, ACE, arginase, testosterone, and uric acid) was done. The cytotoxicity of the crude extracts was also determined. The results revealed that n-butanol induced erectile dysfunction in the rats by decreasing mounting frequency, testosterone and nitric oxide level and simultaneously elevated the activities of arginase and acetylcholinesterase. The plants however, inhibited arginase and acetylcholinesterase when compared to the untreated. Furthermore, the plants’ extracts were able to increase the level of testosterone and nitric oxide. It can be inferred that both plants could be promising natural therapy for erectile dysfunction. Nonetheless, the plants’ extracts are toxic hence should be taken with caution.
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- 2022| Taylor & FrancisFruits contribute to carbon (C) fixation in fruit tree species of savannahwoodlands despite that the C fixed in fruits is rapidly turned back to carbondioxide (CO2) when the fruits decompose or are eaten. The aim of this studywas to determine biomass allocation between fruit components of Strychnosmadagascariensis and Strychnos spinosa and to derive the C stocks seque-strated by fruits. A total of 400 ripe fruits were harvested from trees distrib-uted in seven plots across the UMkhanyakude district. Fruit shell and pulpwere separated from seeds. Puree and juice of S. spinosa were separated bycentrifugation and steam extraction, respectively. Moisture contents of thefruit components were measured. For S. madagascariensis fruits, seeds con-tributed the most biomass (50.2%), followed by the shell (30.8%), and pulphad the least biomass (16.7%). The loss of material was 2.3%. For S. spinosa,the largest part of fruit biomass was in the shell (41.8%), followed by puree(25.6%), seeds (18.6%), juice (6.2%), and pulp (0.9%). The loss of material was6.9%. Fruit dry biomass (FDB; in g) and fruit carbon stocks (CB; in g) were bothrelated to fruit diameter (D; in cm) for S. madagascariensis (FDB = 1.022 ᵡD2.492; CB = 0.463 ᵡ D2.539) and S. spinosa (FDB = 1.015 ᵡ D2.38; CB = 0.198 ᵡD2.821). Proportion values and regression techniques were both valid meth-ods to derive biomass and carbon stocks of the fruit and its components.
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