Background: Khaya senegalensis (Desr.) A. Juss. is a common component of the pharmacopeia's of multiple African groupings which inhabit the areas in which it grows. Amongst these groups there is a myriad of medicinal uses in the treatment of a wide variety of bacterial, fungal and protozoal infections, as well as in the treatment of cancers. This study was undertaken to test K. senegalensis bark extracts for the ability to inhibit microbial and cancer cell growth, and thus to validate traditional African medicinal usage of this plant in treating a variety of diseases. Materials and Methods: K. senegalensis bark powder was extracted by both solvent maceration and subcritical fluid extraction (SFE). The extracts were tested for the ability to inhibit bacterial and G. duodenalis growth. Inhibition of Caco-2 and HeLa cancer cells was evaluated using MTS-based colorimetric cell proliferation assays. Toxicity was evaluated using an Artemia franciscana nauplii bioassay and GC-MS headspace analysis was used to identify phytochemical components. Results: K. senegalensis bark extracts displayed strong inhibitory activity against bacterial triggers of several autoimmune inflammatory diseases. The growth inhibitory activity of the methanolic and subcritical extracts was particularly noteworthy against P. mirabilis (MIC values of 185 and 211µg/mL, respectively against the reference strains). These extracts were similarly potent growth inhibitors of K. pneumoniae and A. baylyi, and were moderate inhibitors (MIC >1000µg/mL) of P. aeruginosa and S. pyogenes growth. The methanolic and subcritical K. senegalensis extracts were also potent inhibitors of G. duodenalis (187 and 328µg/mL, respectively), as well as Caco-2 (268 and 470µg/mL, respectively) and HeLa carcinomas (155 and 174µg/mL, respectively). GC-MS analysis of the SFE extract revealed relative abundances of a variety of mono-and sesquiterpenoids. Furthermore, all K. senegalensis bark extracts were non-toxic in the Artemia franciscana toxicity assay, indicating their safety for therapeutic use. Conclusion: These studies validate traditional African therapeutic usage of K. senegalensis in the treatment of microbial infections, autoimmune inflammatory diseases and some cancers.

Background: Tasmannia lanceolata is an endemic Australian plant with a high anti-oxidant capacity. Liquid solvent extractions of T. lanceolata inhibit bacterial growth and block proliferation of several carcinomas and the gastrointestinal parasite Giardia duodenalis. Despite these promising therapeutic properties, methods for the rapid extraction of large quantities of T. lanceolata are lacking. This study aimed to develop a rapid supercritical extraction method to produce extracts which retain therapeutic propertyes and phytochemistry characteristics. Materials and Methods: T. lanceolata fruit and leaf were extracted by both solvent maceration extraction and supercritical fluid extraction (SFE). The extracts were tested for the ability to inhibit bacterial and G. duodenalis growth. Inhibition of CaCo2 and HeLa cancer cells was evaluated using MTS-based colorimetric cell proliferation assays. Toxicity was evaluated using an Artemia franciscana nauplii bioassay and GC-MS headspace analysis was used to evaluate phytochemical similarity between the extracts. Results: T. lanceolata berry and leaf SFEs displayed strong bacterial growth inhibitory activity against bacterial triggers of autoimmune inflammatory diseases, with efficacies similar to the smaller scale liquid solvent extractions. The growth inhibition of the berry SFE was particularly noteworthy against P. mirabilis and K. pneumoniae, with MIC values of approximately 160 and 190 µg/mL, respectively. The berry and leaf SFE extracts also had similar antiproliferative potencies against G. duodenalis (492 and 375 µg/mL, respectively), CaCo2 (4133 and 3347 µg/mL, respectively) and HeLa carcinomas (2652 and 3497 µg/mL, respectively) to those determined for the corresponding liquid solvent extractions. GC-MS analysis of the berry SFE revealed similar terpenoid components and similar abundances to those in liquid solvent berry extraction. Furthermore, all SFEs were either non-toxic or of only low toxicity in the Artemia franciscana toxicity assay. Conclusion: The T. lanceolata SFE retained the tested therapeutic properties, were nontoxic and had similar phytochemical profiles as smaller scale liquid solvent extractions. Thus, SFE is a viable method of rapidly extracting large masses of T. lanceolata plant material to produce quality extracts which retain therapeutic properties.