Search

α -humulene, a sesquiterpene found in essential oils of various plant species, has garnered interest due to its potential therapeutic applications. This scoping review aims to consolidate α -humuleneʼs evidence base, informing clinical translation, and guiding future research directions. A scoping review was conducted of EMBASE, MEDLINE, and PubMed databases up to 14th July 2023. All studies describing original research on α -humulene extraction, as well as pre-clinical and clinical research, were included for review. Three hundred and forty articles were analysed. α -humulene yields ranged from negligible to 60.90% across plant species. In vitro experiments demonstrated cytotoxicity against adenocarcinomas (such as colorectal, pulmonary, breast, prostatic, lung, and ovarian), with varying responses in other cell models. Mechanistic insights revealed its involvement in mitochondrial dysfunction, diminished intracellular glutathione levels, and the induction of oxidative stress. In rodent studies, oral administration of α -humulene at 50 mg/kg reduced inflammation markers in paw oedema and ovalbumin-induced airway inflammation. Intraperitoneal administration of α -humulene (50 – 200 mg/kg) exhibited cannabimimetic properties through cannabinoid 1 and adenosine A2a receptors. α -humulene also exhibited a multitude of properties with potential scope for therapeutic utilisation. However, there is a paucity of studies that have successfully translated this research into clinical populations with the associated disease. Potential barriers to clinical translation were identified, including yield variability, limited isolation studies, and challenges associated with terpene bioavailability. Consequently, rigorous pharmacokinetic studies and further mechanistic investigations are warranted to effectively uncover the potential of α -humulene. [ABSTRACT FROM AUTHOR]

Based on an ethnobotanical survey, 41 Guinean plant species widely used in the traditional treatment of fever and/or malaria were collected. From these, 74 polar and apolar extracts were prepared and tested for their in vitro antiprotozoal activity along with their cytotoxicity on MRC-5 cells. A potent activity (IC50 < 5 µg/mL) was observed for Terminalia albida, Vismia guineensis, Spondias mombin, and Pavetta crassipes against Plasmodium falciparum; for Pavetta crassipes, Vismia guineensis, Guiera senegalensis, Spondias mombin, Terminalia macroptera, and Combretum glutinosum against Trypanosoma brucei brucei; for Bridelia ferruginea, G. senegalensis, V. guineensis, P. crassipes, and C. glutinosum against Trypanosoma cruzi. Only the extract of Tetracera alnifolia showed a good activity (IC50 8.1 µg/mL) against Leishmania infantum. The selectivity index of the active samples varied from 0.08 to > 100. These results may validate at least in part the traditional use of some of the plant species. [ABSTRACT FROM AUTHOR]