Tropical ulcer plant treatments used by Papua New Guinea's Apsokok nomads

Abstract

Ethnopharmacological relevanceThe tropical ulcer is a debilitating bacterial infection that is common in Papua New Guinea.Deploying healthcare infrastructure to remote and inaccessible rainforest locations is not practical, therefore local plants may be the best treatment option. Here we present an ethnobotanical survey of the tropical ulcer plant medicines used by the semi-nomadic Apsokok who roam the remote central mountains of Papua New Guinea's West New Britain Province. In vitro biological activity in assays relevant to tropical ulcer wound healing is also presented. Materials and methodsFocus groups and semi-structured interviews were used to acquire information on the uses of plants, vouchers of which were identified by comparison with authentic herbarium specimens. Antibacterial disc diffusion assays with Staphylococcus aureus and Fusobacterium ulcerans, MMP-9 enzyme inhibition and dermal fibroblast stimulation assays were carried out on plant saps and aqueous extracts of plant material. LC-MS was used to identify known plant metabolites. ResultsThe ethnobotanical survey identified sixteen species that were used to treat tropical ulcers, all of which were applied topically. A subset of twelve species were investigated further in vitro. Four species produced zones of inhibition with S. aureus, all 12 species provided low level inhibition of MMP-9 and 8 species stimulated dermal fibroblast proliferation, although cytotoxicity occurred at higher concentrations. The extract of Homalium foetidum Benth. inhibited S. aureus and MMP-9 while at lower sub-cytotoxic concentrations stimulated fibroblast proliferation. Trans-3-O-pcoumaroylquinic acid cis-3-O-p-coumaroylquinic acid were detected in the aqueous extract of H.foetidum. ConclusionsTopical application of plant saps to wounds results in very high localised concentrations of plant metabolites which is likely to result in inhibition of MMP proteases. H. foetidum is a candidate plant for tropical ulcer treatment in remote areas.3

Inhibition of Proinflammatory Enzymes and Attenuation of IL-6 in LPS-Challenged RAW 264.7 Macrophages Substantiates the Ethnomedicinal Use of the Herbal Drug Homalium bhamoense Cubitt & W.W.Sm

“…So far, available studies on Homalium spp. have demonstrated relevant biological activities frequently related to their ethnomedicinal uses, such as antibacterial [2], antidiabetic [3], antinociceptive [4] and anti-inflammatory [3,4].…”

“…is generally referred to as a wound healing plant [1,5]; leaves from Homalium foetidum Benth. are used by tribes from Papua New Guinea to treat topical ulcers and subcutaneous skin infections [2,6]. While there are no available studies on the biological properties of Homalium bhamoense Cubbit & W.W.Sm., surveys indicate its utility against common ailments, such as joint pain and fever [1].…”

Evaluation of Cypholophus macrocephalus sap as a treatment for infected cutaneous ulcers in Papua New Guinea

“…Sulphated flavonoids have been previously identified from certain plant families, such as Arecaceae, Asteraceae, Bixaceae, Dilleniaceae, Frankeniaceae, Gramineae, Guttiferae, Juncaceae, Malvaceae, Tamaricaceae, Umbelliferae and Verbenaceae (Teles et al, 2018). Quercetin-O-sulphates (including single and multi-sulphate esters) have been frequently observed in the Asteraceae (Harborne and Baxter, 1999 (Prescott et al, 2012;Prescott et al, 2017). However, the complexity of wound healing biology is such that a wide range of modes of action, unrelated to antibacterial activity, could potentially contribute to in vivo efficacy.…”

“…We have been carrying out ethnopharmacological research in the Kandrian inland area that extends into the foothills of the Whiteman Range, since 1998. Our focus has been on plants used to treat cutaneous leg ulcers, which are a highly common bacterial infection that until recently has received relatively little attention in tropical disease research (Prescott et al, 2012;Prescott et al, 2015;Prescott et al, 2017). The focus of this research is to identify promising plant saps that could be used as first-line treatments for cutaneous ulcers, in remote areas that lack access to basic health facilities.…”

Rationale, experience and ethical considerations underpinning integrated actions to further global goals for health and land biodiversity in Papua New Guinea

“…Second, we will champion traditional pharmacy when it can be demonstrated to be effective as a result of its characteristic features rather than any expectant beliefs (Howick 2017). This has been done elsewhere in PNG with tropical ulcer treatments (Prescott et al 2017). Third, in the Madang region medical pluralism is common.…”