Evaluation of phytochemical and ethnomedicinal uses of Bersama swinnyi E. Phillips (Francoaceae)

Bersama swinnyi is a small tomedium-sized tree endemic to evergreen forests of the Eastern Cape and KwaZulu-Natal provinces of South Africa. The species is widely used as traditional medicine throughout its distributional range in the country. A systematic review of the literature studies was carried out to document the phytochemical and ethnomedicinal uses of B. swinnyi. The results of the current study are based on literature survey conducted using various search engines such asWeb of Science, Elsevier, Pubmed, Google Scholar, Springer, Science Direct, Scopus, Taylor and Francis, and pre-electronic sources such as books, book chapters, scienti ic journals and other grey literature obtained from the University library. The bark and root extracts of B. swinnyi are mainly used as aphrodisiac, charm and ritual purposes, and traditional medicine for infertility, impotence, leprosy and menstrual problems. Chemical constituents identi ied from B. swinnyi include 23hydroxy betulinaldehyde, 24-propylcholestan-7,15,20-triol, betunal, lupeol, oleanolic acid and swinniol. Bersama swinnyi is a valuable medicinal plant species and future research should focus onmore exploratory research to gain a better understanding of the ethnopharmacological properties of the species. There is also a need for extensive toxicological evaluations of crude extracts and compounds isolated from the species since B. swinnyi contains potentially toxic compounds.

Bersama Swinnyi, Ethnopharmacology, Francoaceae, Indigenous Knowledge, Melianthaceae, Traditional Medicine A Bersama swinnyi is a small to medium-sized tree endemic to evergreen forests of the Eastern Cape and KwaZulu-Natal provinces of South Africa. The species is widely used as traditional medicine throughout its distributional range in the country. A systematic review of the literature studies was carried out to document the phytochemical and ethnomedicinal uses of B. swinnyi. The results of the current study are based on literature survey conducted using various search engines such as Web of Science, Elsevier, Pubmed, Google Scholar, Springer, Science Direct, Scopus, Taylor and Francis, and pre-electronic sources such as books, book chapters, scienti ic journals and other grey literature obtained from the University library. The bark and root extracts of B. swinnyi are mainly used as aphrodisiac, charm and ritual purposes, and traditional medicine for infertility, impotence, leprosy and menstrual problems. Chemical constituents identi ied from B. swinnyi include 23hydroxy betulinaldehyde, 24-propylcholestan-7,15,20-triol, betunal, lupeol, oleanolic acid and swinniol. Bersama swinnyi is a valuable medicinal plant species and future research should focus on more exploratory research to gain a better understanding of the ethnopharmacological properties of the species. There is also a need for extensive toxicological evaluations of crude extracts and compounds isolated from the species since B. swinnyi contains potentially toxic compounds.

INTRODUCTION
Bersama swinnyi E. Phillips is a small to mediumsized tree belonging to the Francoaceae family. Francoaceae is a small family consisting of about seven genera, namely Balbisia Cav., Bersama Fresen., Francoa Cav., Greyia Hook. & Harv., Melianthus L., Tetilla DC. and Viviania Cav (Chase et al., 2016). Several researchers in the past placed the genus Bersama in the Melianthaceae family (Phillips, 1922;Verdcourt, 1950). But numerous morphological characters such as habit and leaf form, in lorescence and loral characteristics, phytochemical constituents and molecular data supported placing of the genus Bersama in Francoaceae instead of Melianthaceae family (Chase et al., 2016;Maroyi, 2020). The genus Bersama consists of shrubs and small trees recorded in the Afromontane vegetation, tropical lowland habitats and margins of evergreen forests in sub-Saharan Africa but conspicuously absent in the Congo basin (Decraene et al., 2001;Linder, 2007). Seven species which include B. abyssinica Fresen., B. lucens (Hochst.) Szyszyl., B. palustris L. Touss., B. swinnyi, B. swynnertonii Baker f., B. tysoniana Oliv, and B. yangambiensis L., Touss. are recognized within the Bersama genus (Verd-court, 1957(Verd-court, , 1989. The genus name Bersama refers to the Ethiopian name for this genus (Palmer and Pitman, 1972). The species name swinnyi is in honour of a British born South African forester and naturalist Henry Hutchinson Swinny  who claimed that the species consisted of two forms, one form growing up to 27 metres in height with a stem diameter of one metre and the second form characterized by a trunk diameter of 0.3 to 0.5 metres (Palmer and Pitman, 1972).
Bersama swinnyi is a small to medium-sized tree endemic to evergreen forests, forest margins and sandstone outcrops of the Eastern Cape and KwaZulu-Natal provinces of South Africa (White, 1966;White and Styles, 1986). The English common names of B. swinnyi include "bitter-bark", "coast bersama", "coastal bersama", "coastal white ash" and "Swinny's bersama" (Grace et al., 2003;Grace, 2002). The stems are tall and slender reaching a height of 15 metres (Palgrave, 2002). The bark of B. swinnyi is brown, rough and furrowed, the branches velvety when young but becoming smooth with age. The leaves of B. swinnyi are compound, made up of 4 to 7 pairs of lea lets and a terminal lea let, crowded towards the ends of the branches. The lea lets are opposite or nearly opposite, elliptic or oblong in shape, the tips rounded or pointed and sometimes notched. The base of the lea let is rounded or slightly narrowed, untoothed, the midrib and lateral veins distinct, smooth, the common leaf stalk hairy when young and smooth when mature. The lowers are bisexual, in stout axillary racemes, clustered in spikes at the tips of branches, greenish white in colour, interspersed with silvery and silky bracts Wyk, 2007, 2013). The fruits are four-valved capsules, knobby, brown and woody, which split open when mature and partly enveloped by a yellowish aril. The seeds are oval in shape and red-brown in colour. Bersama swinnyi is sometimes confused with B. tysoniana Oliv. but the bark of the former species is characterized by a burning taste lacking in the later species. This burning taste is characteristic of B. swinnyi and is said to be very strong, and dull the taste for hours after the bark has been placed in the mouth (Palmer and Pitman, 1972;Palgrave, 2002). The harvested bark of B. swinnyi is readily diagnosed by the presence of calcium oxalate crystals, visible in the broken cross section of dried material (Cunningham, 2001;Grace et al., 2003). The species has been recorded at an altitude ranging from 150 m to 1405 m above sea level (Germishuizen and Meyer, 2003).
The bark of B. swinnyi is traded in informal herbal medicine markets in the Gauteng (Williams et al., 2001;Williams, 2003) and KwaZulu Natal provinces (Cunningham, 1993;Netshiluvhi, 1996) in South Africa. Research towards end of the 20 th century and beginning of 21 st century revealed that B. swinnyi population was declining in the KwaZulu-Natal province (Cunningham, 1988;Monkhe, 1997). Bersama swinnyi was heavily exploited as commercial source of bark products sold in informal herbal medicine markets in both the KwaZulu-Natal and Gauteng provinces. Over-exploitation of the species for commercial purposes led to the species becoming rare in the wild (Cunningham, 1988;Monkhe, 1997). Research by Ndawonde (2006) categorized B. swinnyi as a species facing an extremely high risk of extinction in the wild and in need of protection in the northern Zululand. Although several reports highlighted that B. swinnyi is threatened with extinction mainly because it is endemic and experiencing signi icant habitat loss and overexploited as herbal medicines, but the IUCN Red List Categories and Criteria version 3.1 of threatened species used to assess the conservation status of the species by Raimondo et al. (2009) revealed that the species is of Least Concern (LC) as the population numbers of the species stabilized over the years. Bersama swinnyi is listed as an important medicinal plant species in South Africa and the general characteristics of the species are outlined in the monograph "medicinal plants of South Africa" . Therefore, the aim of this review is to provide a comprehensive appraisal of the phytochemical and ethnomedicinal uses of B. swinnyi.

MATERIALS AND METHODS
Several electronic databases were searched which included Web of Science, Elsevier, Pubmed, Google Scholar, Springer, Science Direct, Scopus, Taylor and Francis. Additional information was obtained from pre-electronic sources such as books, book chapters, scienti ic journals and other grey literature obtained from the University library. The relevant terms Bersama swinnyi were paired with keywords such as "medicinal uses of Bersama swinnyi", "phytochemicals of Bersama swinnyi", "biological activities of Bersama swinnyi", "ethnobotany of Bersama swinnyi", and various other synonyms and common names of the plant species. The ultimate goal of this search was to explore articles that investigated the phytochemical and ethnomedicinal uses of B. swinnyi.
Similarly, research by Ayeleso and Matumba (2017) showed that the compound oleanolic acid and its derivatives are characterized by anti-hypertensive, anti-tumour, anti-diabetic, anti-in lammatory, anti-cancer, antimicrobial, anti-parasitic, hepatoprotective and antioxidant activities. Therefore, the extracts of

CONCLUSION
This review showed that B. swinnyi is widely used as herbal medicine and the species is characterized by several phytochemical compounds. Documentation of the medicinal uses, phytochemistry and pharmacological properties of B. swinnyi is crucial as this information forms the baseline data required for future research and development of healthpromoting and pharmaceutical products. Findings from this study showed that there are still some research gaps in the phytochemistry, pharmacological and toxicological properties of the species. More rigorous research is required aimed at evaluating various plant parts used as herbal medicines, assessing their phytochemistry, pharmacological and toxicological properties.

ACKNOWLEDGEMENT
I am grateful to the reviewers who kindly commented on my manuscript.