Indian borage (Plectranthus amboinicus) has antifungal activity according to some researchers which would be especially valuable in stored food products. The oil (IBO) was assessed against various fungi using the well diffusion assay. IBO exhibited broad toxicity against a range of aspergillus spp. – Aspergillus flavus, Aspergillus niger, Aspergillus ochraceus CFR 221, Aspergillus oryzae, various yeasts and moulds such as Candida versatilis, Fusarium sp. GF-1019, Penicillium sp., and Saccharomyces cerevisiae. A particular measure was inhibition of theradial mycelial growth of the fungi.
IBO completely inhibited the mycotoxin, ochratoxin (OTA) produced by the toxigenic strain A. ochraceus CFR 221 at 500 ppm when grown in yeast extract sucrose medium. Also, the application of IBO at 100 mg/g in food samples inhibited growth of A. ochraceus in food systems including maize, groundnut and poultry feed. No detectable amount of ochratoxin was identified at high moisture levels such as 30%, even after seven days.
Again, another natural antifungal agent based on the oil might be possible. Does it impart a flavour – not sure but the search for such natural agents continues. Indian Borage has also been used in traditional medicine for modifying the appetite and thus has powerful credentials for weight management.
Murthy, P. S., Ramalakshmi, K., & Srinivas, P. (2009). Fungitoxic activity of Indian borage (Plectranthus amboinicus) volatiles. Food Chemistry, 114(3), pp. 1014-1018