Phytochemical investigation of the leaf latex of Aloe trichosantha by preparative TLC gave two closely related anthrones, aloin A/B (1) and aloin-6'-O-acetate A/B (2). The identity of the compounds was established from HRESI-MS, 1H, 13C, DEPT, HMQC and HMBC spectral and chemical data. Whilst aloin A/B occurs in several Aloe species, aloin-6'-O-acetate A/B was isolated for the first time. The isolated compounds inhibited growth of several bacterial and fungal pathogens with minimum inhibitory concentration (MIC) from 10 to 400 μg/mL and 800 to 1000 μg/mL, respectively.
SmithG.F., SteynE.M.A., VictorJ.E., CrouchN.R., GoldingJ., Hilton-TaylorC. (2000) Aloaceae: the conservation status of Aloe in South Africa: an updated synopsis. Bothalia, 30, 206–211.
2.
DagneE., BisratD., ViljoenA., Van WykB. (2000) Chemistry of Aloe species. Current Organic Chemistry, 4, 1055–1078.
3.
(a) DemissewS., NordalI. (2010) Aloes and Lilies of Ethiopia and Eritrea. 1st ed. Shama Books, Addis Ababa, Ethiopia, pp. 42–78; (b) Oumer A. (2013) Isolation and characterization of antimicrobial and antimalarial anthrones from the leaf latex of Aloe trichsantha Berger (Aloaceae). MSc Thesis, Addis Ababa University, Ethiopia.
4.
(a) AsamenewG., BisratD., MazumderA., AsresK. (2011) In vitro antimicrobial and antioxidant activities of anthrone and chromone from the latex of Aloe harlana. Phytotherapy Research, 25, 1756–1760; (b) Minale G, Bisrat D, Asres K, Mazumder A. (2014) In vitro antimicrobial activities of anthrones from the leaf latex of Aloe sinana Reynolds. International Journal of Green Pharmacy, 8, 7–12.
5.
(a) MazumderR., DastidarS.G., BasuS.P., MazumderA., SinghS.K. (2004) Antibacterial potentiality of Mesua ferrea Linn. flowers. Phytotherapy Research, 18, 824–826; (b) National Committee for Clinical Laboratory Standards. (2000) Methods for dilution antimicrobial susceptibility test for bacteria that grow aerobically, 5th ed. Wayne, PA: Approved standard M7-A4, NCCLS.
6.
(a) FarahM.H., AnderssonR., SamuelssonG. (1992) Microdontin A and B: two new aloin derivatives from Aloe microdonta. Planta Medica, 58, 88–93; (b) Manitto P, Monti D, Speranza G. (1990) Studies on Aloe. Part 6. Conformation and absolute configuration of aloins A and B and related 10-C-Glucosyl-9-anthrones. Journal of the Chemical Society Perkin TransectionsI, 1297–1300.
7.
ViljoenA.M. (1999) A chemotaxonomic study of phenolic leaf compounds in the genus Aloe. PhD Thesis, Rand Afrikaans University, South Africa.
8.
KambiziL., SultanaN., AfolayanA.J. (2004) Bioactive compounds isolated from Aloe ferox: a plant traditionally used for the treatment of sexually transmitted infections in the Eastern Cape, South Africa. Pharmaceutical Biology, 42, 636–639.
9.
PatroneJ.B., SteinD.C. (2007) Effect of gonococcal lipooligosaccharide variation on human monocytic cytokine profile. Biomedcentral Microbiology, 7, 1–15.
10.
(a) LawrenceR., TripathiP., JeyakumarE. (2009) Isolation, purification and evaluation of antibacterial agents from Aloe vera. Brazilian Journal of Microbiology, 40, 906–915; (b) Savoia D. (2012) Plant-derived antimicrobial compounds: alternatives to antibiotics. Future Microbiology, 7, 979–990.
