Potential of indigenous fruit-bearing trees to curb malnutrition, improve household food security, income and community health in Sub-Saharan Africa: A review

Process optimisation for enzymatic clarification of indigenous wild watermelon (Citrullus lanatus) juice

A fundamental step in improving the quality and consumer acceptability of wild watermelon (Citrullus lanatus) is the process of juice clarification. The aim of this research was to investigate the physicochemical properties of crude wild watermelon (Citrullus lanatus) juice and to optimise the processing conditions, incubation time, incubation temperature and enzyme concentration for the enzymatic clarification of the crude juice. Crude wild watermelon juice samples were treated with pectinase enzyme in different concentrations (0.05 to 0.15 w/w%), at different incubation temperatures (30-50 oC) and for different incubation durations (60-180 min). The effects of the different treatments on turbidity, clarity, viscosity, lightness, and brix were determined. The response models adequately predicted turbidity, clarity, and viscosity at R2 > 0.5, but not lightness considering that R2 < 0.5. The model was statistically significant in predicting turbidity (R2 = 0.86), clarity (R2 = 0.81), viscosity (R2 = 0.97) and brix (R2 = 0.94) - but not lightness (R2 = 0.24) at p < 0.05. The enzyme concentration did not significantly affect turbidity, clarity, and lightness, but it did significantly affect brix positively (p < 0.05). Response surface methodology software was used to determine optimal clarification conditions. In conclusion, the optimum conditions for crude watermelon juice clarification were 0.15 w/w% enzyme concentration, 60 min incubation time and 60 oC incubation temperature. The optimum output parameters were 14.18 NTU for turbidity, 0.04 Abs for clarity, 52.30 L* value for lightness, 1.96 cps for viscosity and 3.08% for Brix.

The Future of Food: Domestication and Commercialization of Indigenous Food Crops in Africa over the Third Decade (2012–2021)

This paper follows the transition from ethnobotany to a deeper scientific understanding of the food and medicinal properties of African agroforestry tree products as inputs into the start of domestication activities. It progresses on to the integration of these indigenous trees as new crops within diversified farming systems for multiple social, economic and environmental benefits. From its advent in the 1990s, the domestication of indigenous food and non-food tree species has become a global programme with a strong African focus. This review of progress in the third decade is restricted to progress in Africa, where multi-disciplinary research on over 59 species has been reported in 759 research papers in 318 science publications by scientists from over 833 research teams in 70 countries around the world (532 in Africa). The review spans 23 research topics presenting the recent research literature for tree species of high priority across the continent, as well as that in each of the four main ecological regions: the humid zone of West and Central Africa; the Sahel and North Africa; the East African highlands and drylands; and the woody savannas of Southern Africa. The main areas of growth have been the nutritional/medicinal value of non-timber forest products; the evaluation of the state of natural resources and their importance to local people; and the characterization of useful traits. However, the testing of putative cultivars; the implementation of participatory principles; the protection of traditional knowledge and intellectual property rights; and the selection of elite trees and ideotypes remain under-researched. To the probable detriment of the upscaling and impact in tropical agriculture, there has been, at the international level, a move away from decentralized, community-based tree domestication towards a laboratory-based, centralized approach. However, the rapid uptake of research by university departments and national agricultural research centres in Africa indicates a recognition of the importance of the indigenous crops for both the livelihoods of rural communities and the revitalization and enhanced outputs from agriculture in Africa, especially in West Africa. Thus, on a continental scale, there has been an uptake of research with policy relevance for the integration of indigenous trees in agroecosystems and their importance for the attainment of the UN Sustainable Development Goals. To progress this in the fourth decade, there will need to be a dedicated Centre in Africa to test and develop cultivars of indigenous crops. Finally, this review underpins a holistic approach to mitigating climate change, as well as other big global issues such as hunger, poverty and loss of wildlife habitat by reaping the benefits, or ‘profits’, from investment in the five forms of Capital, described as ‘land maxing’. However, policy and decision makers are not yet recognizing the potential for holistic and transformational adoption of these new indigenous food crop opportunities for African agriculture. Is ‘political will’ the missing sixth capital for sustainable development?

Ethnobotanical Uses, Nutritional Composition, Phytochemicals, Biological Activities, and Propagation of the Genus Brachystelma (Apocynaceae)

The Brachystelma genus (family: Apocynaceae) consists of geophytes that are traditionally utilised among rural communities, especially in East Africa, southern Africa, West Africa, and northern and western India. Apart from being used as a food source, they are indicated as treatment for ailments such as colds, chest pains, and wounds. This review provides a critical appraisal on the ethnobotanical uses, nutritional value, phytochemical profiles, and biological activities of Brachystelma species. In addition, we assessed the potential of micropropagation as a means of ensuring the sustainability of Brachystelma species. An inventory of 34 Brachystelma species was reported as a source of wild food and traditional medicine (e.g., respiratory-related conditions, pains, and inflammation) across 13 countries, predominantly in Africa and Asia. Brachystelma circinnatum and Brachystelma foetidum were the most popular plants based on the high number of citations. Limited data for the nutritional content was only available for Brachystelma edulis and Brachystelma naorojii, as well as phytochemical profiles (based on qualitative and quantitative techniques) for five Brachystelma species. Likewise, a few Brachystelma species have evidence of biological activities such as antimicrobial, antioxidant, and acetyl cholinesterase (AChE) inhibitory effects. Extensive studies on Brachystelma togoense have resulted in the isolation of four compounds with therapeutic potential for managing different health conditions. As a means of contributing to the sustainability of Brachystelma species, micropropagation protocols have been devised for Brachystelma glabrum, Brachystelma pygmaeum, Brachystelma ngomense, and Brachystelma pulchellum. Nevertheless, continuous optimisation is required to enhance the efficiency of the micropropagation protocols for these aforementioned Brachystelma species. Despite the large number of Brachystelma with anecdotal evidence as food and medicine, a significant number currently lack empirical data on their nutritional and phytochemical profiles, as well as their biological activities. The need for new propagation protocols to mitigate the declining wild populations and ensure their sustainability remains pertinent. This is important should the potential of Brachystelma species as novel food and medicinal products be achieved.

African Lives Matter: Wild Food Plants Matter for Livelihoods, Justice, and the Environment—A Policy Brief for Agricultural Reform and New Crops

International agricultural policies to address hunger and malnutrition in the tropics and sub-tropics have typically been based on approaches to the intensification of farming systems effective in industrialised economies where the social, economic, and environmental conditions and the infrastructure are very different to those in Africa. The consequence of this short-sightedness has been that agricultural productivity, dependent on ecosystem services from natural capital, has declined in Africa due to ecological and environmental collapse. This has undermined the livelihoods of the millions of smallholder farmers living on the brink of the cash economy, leading to severe social injustice. This review summarises advances in smallholder agriculture’s sustainable intensification in the tropics and sub-tropics, leveraging the domestication and commercialisation of wild indigenous tree species that produce nutritious, marketable, and useful food and non-food products. These are grown within diversified and multifunctional farming systems together with conventional food staples and local orphan crops to reduce land degradation, pollution, water extraction, and nutrient mining while promoting services such as pollination and other ecological functions. The benefits arising from this approach simultaneously address hunger, malnutrition, poverty, social injustice, and a stagnant economy, as well as important global issues such as climate change, loss of biodiversity and environmental degradation. Addressing these issues may also reduce the risk of future pandemics of zoonotic diseases, such as COVID-19. This set of serious global issues epitomise our divided and dysfunctional world and calls out for action. Enhancing sustainable smallholder productivity using indigenous and wild foods is an important international policy and business intervention, vital for achieving the 2030 Sustainable Development Goals and the rebalancing of the global economy by restoring natural capital within new African indigenous food industries.

Exploring the Resource Value of Transvaal Red Milk Wood (Mimusops zeyheri) for Food Security and Sustainability: An Appraisal of Existing Evidence

Many African countries are endowed with rich biodiversity with enormous nutritional and economic prospects, but the majority of these resources are not fully harnessed. Exploring these neglected resources, for example, the Transvaal red milkwood tree [(Mimusops zeyheri) Sond. family: Sapotaceae] is of paramount importance for food and nutritional security as well as economic prosperity. This review provides a critical appraisal of the nutritional and health benefits as well as the economic potential of Mimusops zeyheri. The plant is known for its diverse uses among rural communities. In folk medicine, the decoction from the bark and leaves of Mimusops zeyheri are used for treating wounds and ulcers, while the root is used as an infusion taken to treat candidiasis and other health issues. The nutritional profile of the fruit tree is similar to popular exotic fruits and richer in vitamin C when compared to guava and orange. Mimusops zeyheri is a rich source of vitamins, protein, and fatty acids. Based on the rich chemical pool, especially in the fruit and seeds, it has the potential to provide an accessible, readily available, and affordable enriched functional food with valuable health benefits. However, the successful exploration of Mimusopszeyheri for food security and sustainability requires multidisciplinary research. This will help achieve the envisaged food-nutrition security and poverty alleviation potential of the plant, especially among local communities.

An Exploratory Study on the Diverse Uses and Benefits of Locally-Sourced Fruit Species in Three Villages of Mpumalanga Province, South Africa

Globally, the potential of indigenous and neglected fruit species is continuously being recognized. In the current study, we explored the uses and benefits of locally available fruit species among the Mapulana people in Bushbuckridge Local Municipality. An ethno-botanical survey was conducted using in-depth interviews to record the names of the fruit species, their uses, seasonal availability, and occurrence in three villages, namely, Mokhololine, Motlamogatsane, and Rooiboklaagte B. Forty-one (41) participants aged 23 to 89 years old, identified by community members as knowledgeable on the utilization of fruit species, were interviewed. The frequency of citation (FC), use value (UV), and use report (UR) of the locally sourced fruit species were determined. The study revealed thirty-one (31) indigenous/naturalized plants belonging to 17 families with Anacardiaceae (four species) and Rubiaceae (three species) as the dominant ones. Approximately 48% of the 31 plants had FC of 100%, suggesting their high popularity in the study area. The identified plants had diverse uses that were categorized into six (6) groups and mainly dominated by food (59%) and medicine (34%). Strychnos madagascariensis had the highest (0.56) UV while Berchemia discolor, Parinari capensis, Parinari curatellifolia, and Sclerocarya birrea had the highest (6) URs. Overall, these locally sourced fruit species still play a significant role in the daily lives of the Mapulana people. The identified fruit species have the potential to be considered as alternative sources to meet the dietary requirements and health needs, especially in rural communities.

Ziziphus mucronata Willd. (Rhamnaceae): it's botany, toxicity, phytochemistry and pharmacological activities

Ziziphus mucronata is an important multi-purpose plant species that has been used in African traditional medicine for ages in the treatment of various devastating human and animal infections. The current paper is aimed at providing an overview of uses, toxicology, pharmacological properties and phytochemistry of Z. mucronata. The information used in the current work was retrieved using various search engines, including Pubmed, Science Direct, Google Scholar, Scielo, SciFinder and Scopus. The key words used included Ziziphus mucronata, secondary metabolites, chemistry, biological activity and pharmacology, anti-inflammatory, antimicrobial, antifungal, antiviral, ethnobotanical survey, medicinal uses, safety, toxicology and other related words. Out of the 46 infections which the plant species is used to treat, the most common uses includes sexually transmitted infections, skin infections, diarrhoea and dysentery, respiratory and chest complaints and gynaecological complaints (citations ≥6). Pharmacologically, the plant species exhibited a potential antimicrobial activity yielding a minimum inhibitory concentration of <1 mg/ml against important pathogens which includes Mycobacterium tuberculosis, Moraxella catarrhalis, Staphylococcus aureus, Escherichia coli, Propionibacterium acnes, Candida albicans, Cryptoccoos neoformans amongst other microorganisms. Furthermore, the extracts and compounds from Z mucronata revealed potent antiviral, antioxidant, anti-inflammatory and other activities in vitro. Phytochemically, cyclo-peptide alkaloids (commonly called mucronines) dominates and in conjunction with triterpenes, flavonoids, phenolic acids and anthocyanins. Besides these compounds, the plant species exhibited the presence of important in minerals. These phytoconstituents may well explain the reported biological activities. Although the extracts revealed no cytotoxic effect to Vero cells, further toxicological characteristics of the plant species still needs to be explored. There is also a need to carry out the comprehensive safety profiles of the plant species, including heavy metal detection. Although the plant species revealed important biological activities, which includes antimicrobial, antiviral, anti-diabetic, anti-inflammatory, anti-oxidant, anti-plasmodial, anthelmintic, and anti-anaemic activity in vitro, further research is needed to explore the in vivo studies, other compounds responsible for such activities and the mechanisms of action thereof. Such activities validates the use of the plant species in traditional medicine. The data on the possible use of the plant species in the treatment of diarrhoea, sexually transmitted infections, skin related and gynaecological complaints are scant and still needs to be explored and validated both in vitro and in vivo. Furthermore, the anticancer and anthelmintic activity of the plant species also needs to be explored.

African Adansonia digitata fruit pulp (baobab) modifies provitamin A carotenoid bioaccessibility from composite pearl millet porridges

Food-to-food fortification of staple cereal products using nutrient-dense plants shows promise to address multiple micronutrient deficiencies including vitamin A, iron and zinc in Sub-Saharan Africa. However, there is limited information on the potential interaction effects that such food-to-food fortified strategies may have on individual micronutrient bioavailability. The main objective of the current study was to investigate the impact of incorporating Adansonia digitata (baobab fruit pulp), a mineral-rich plant material, on the delivery of carotenoids from a composite cereal porridge. Formulations of native fruit/vegetable-cereal composites were screened for interactions which could influence both bioaccessibility and subsequent intestinal uptake of provitamin A carotenoids. Proportions of pearl millet flour and plant materials were dry blended to provide composite cereal porridges with total provitamin A carotenoid concentrations ranging from 3590.7 ± 23.4 to 3698.5 ± 26.5 μg/100 g (fw) and baobab concentrations ranging from 0 to 25% (dw).While there were no significant differences in provitamin A carotenoid bioaccessibility from porridge formulations containing 5 or 15% baobab, inclusion of 25% baobab resulted in a significant (p < 0.05) decrease in bioaccessibility (13.3%) as compared to the control (23.8%). Despite the reduced bioaccessibility, 6 h uptake efficiency of provitamin A carotenoids by Caco-2 human intestinal cells was not significantly altered by 25% baobab inclusion. These findings suggest that the inhibitory effects on carotenoid micellarization (bioaccessibility) observed with increased baobab addition may not ultimately limit the bioavailability of carotenoids.

Ethnobotanical uses, biological activities and chemical properties of Kei-apple [Dovyalis caffra (Hook.f. & Harv.) Sim]: An indigenous fruit tree of southern Africa

ETHNOPHARMACOLOGICAL RELEVANCE

Dovyalis caffra (Hook.f. & Harv.) Sim (commonly called Kei-apple) is an indigenous fruit tree that has medicinal values for various ethnic groups in southern Africa.

AIM OF THE REVIEW

This review aims to provide a critical appraisal of the existing knowledge on the ethnobotanical value, biological activities and phytochemicals of Dovyalis caffra. In addition, the potential of producing a functional health product from Kei-apple due to its therapeutic effects and rich pool of phytochemicals was explored.

METHODS

A detailed literature search was conducted using various online search engines, such as Scopus, Google Scholar, Mendeley and Web of Science. Additional information was sourced from ethnobotanical literature focusing on southern African flora.

RESULTS

Dovyalis caffra has diverse uses in local and popular medicine, specifically for relieving pain and rheumatism in humans. Ethno-veterinary potential of Kei-apple has also been documented in East Africa. Non-medicinal uses of the tree include its role in biological hedging and as a traditional herb for African magical purpose. Regarding its biological activities, polar extracts from the seeds exhibited noteworthy antibacterial (minimum inhibitory concentration of 1 μg/ml against Staphylococcus aureus) activity. Quantitative analysis (e.g. GC-MS, HPLC) indicated the presence of a rich (>80) pool of chemicals, including sterols, phenolic acids and fatty acids from different parts of the plant while 11 compounds have been isolated from its leaves and twigs.

CONCLUSIONS

Dovyalis caffra has been tested for various biological activities and the extracts (seeds in particular) demonstrated promising antibacterial potential. A lack of alignment between the ethno-medicinal uses and existing biological screenings was observed, indicting the need for anti-inflammatory and anti-rheumatism potential of Dovyalis caffra to be explored. In vivo validation of antibacterial and anti-parasitic activities against clinical bacterial strains and parasites, respectively is required. Other areas that need investigation are safety evaluations and development of integrated cultivation approach in order to fully explore the plant's potential.

Assessing Nutritional Traits and Phytochemical Composition of Artisan Jams Produced in Comoros Islands: Using Indigenous Fruits with High Health-Impact as an Example of Biodiversity Integration and Food Security in Rural Development

In the Comoros Islands, as in other developing countries, malnutrition and food insecurity affect a very large percentage of the population. Developing fruit-based products in order to make profit, reduce poverty and improve indigenous people diet could be very important for local population of countries as Comoros Islands. The aim of the present work was to study the chemical composition of jams and jellies produced from seven fruit species harvested in Grand Comore Island. The following parameters were studied sugars and organic acids, total phenolics, total anthocyanins and high-performance liquid chromatography (HPLC) fingerprint of the main phytochemicals. Antioxidant activity was also measured. A multivariate approach (Principal Component Analysis) was performed in order to better characterize the products and to set a potential analytical tool for jam characterisation. Results showed that the analysed products are a good source of polyphenolic constituents, as caffeic and gallic acids, catechin and quercetin and volatile compounds, as limonene and γ-terpinene: these molecules may be considered as suitable markers for these fruit-derived products as characterizing the chromatographic patterns. The characterisation of these products and their nutritional and nutraceutical traits is important as valorisation of local food production for poverty reduction and rural development. Further benefits of this approach include the maintenance of local agro-biodiversity as raw material for fruit-based products and the strengthening of food security practices.

Nutraceutical and Ethnopharmacological Properties of Vangueria infausta subsp. infausta

Vangueria infausta subsp. infausta (VI) is a nutraceutical with plant parts valued in several cultures for its medicinal properties. Traditionally, VI is used against gastro-intestinal disorders, malaria, pneumonia, cough, menstrual problems, parasitic worms, chest complaints, snake bites, infertility, fever, candidiasis and abdominal pains. This study aims to critically summarize the nutraceutical properties, phytochemistry and pharmacology of VI with a view to provide baseline data required for further investigations on this plant. Relevant information on the nutraceutical and ethnopharmacological properties of VI was collected from established scientific databases such as ScienceDirect, SciFinder, PubMed, Google Scholar, Medline, and SCOPUS. Additionally, books, book chapters and conference papers were also consulted to access other important information. Comparative analysis of the literature revealed that VI is an important neutraceutical plant in east and southern Africa, used as herbal medicine in 69% of the countries where the species is native. Phytochemical studies revealed the presence in VI of fatty acids, flavonoids, iridoid lactones and triterpenoids. Based on in vitro and animal studies, the species exhibited antibacterial, antimycobacterial, antifungal, anti-inflammatory, antileishmanial, antioxidant, antiplasmodial, antifeedant and prostaglandin synthesis inhibitory activities. Pharmacological studies have provided supporting evidence for the therapeutic value of VI, however, detailed toxicological and clinical trials are required to assess efficacy of the species.

The role of wild fruits and vegetables in delivering a balanced and healthy diet

Without a doubt, fruits and vegetables are important components of a balanced and healthy diet. However, their consumption is very low in the world, with the lowest figures being reported in sub-Saharan Africa. The low consumption of fruits and vegetables means unbalanced and unhealthy diets, which has been linked to various diseases and conditions associated with increased mortality rates in worst cases. Poverty is the major contributor to the low consumption of fruits and vegetables in the majority of cases. However, the world, including sub-Saharan Africa, is endowed with numerous wild fruit and vegetable species which can be exploited and incorporated into the diets and help solve some nutrition related concerns. Therefore, in this review, we explore literature on wild fruits and vegetables with a special emphasis on some of the poorest regions of the world and where the lowest consumption figures are reported; their nutritional compositions; the status of their consumption and their role in the diet with a view to uncover their possible role in delivering a healthy and balanced diet as well as helping lower food and nutrition insecurity. A total of 396 articles were downloaded and analysed but only 213 were considered for this review. The results of the search indicate that wild fruits and vegetables are nutritionally rich and high in phytochemicals, especially antioxidants and therefore can possibly play a significant and positive role in delivering a healthy and balanced diet. However, the major challenge is the acceptability, accessibility as well as a lack of interest in wild fruits and vegetables and sheer neglect. People need to be educated using various forms of media on the nutritional and health benefits of these wild food plants with a view to bring them from the forest to the plate. Researchers need to channel more efforts towards domesticating them for ease of access, among other reasons. Governments need to incentivise the subsistence or commercial production of wild fruits and vegetables in order to encourage farmers to cultivate them. However, seeds and/or seedlings need to be made available and affordable to the farmers. The 'hidden treasures' in the forests in the form of edible plants could easily play a positive and huge role in delivering a balanced and healthy diet, especially in poor parts of the world.