<i>In vivo</i> anti-inflammatory activity of two anthrones from the leaf latexes of <i>Aloe adigratana</i> reynolds and <i>Aloe elegans</i> todaro

Abstract

Aloe adigratana Reynolds and Aloe elegans Todaro are traditionally used for the treatment of various illnesses, including wounds, infections and inflammation in northern Ethiopia. Despite their morphological differences, the leaf latexes of both Aloes showed the same chemical profile when analyzed by TLC. Further phytochemical investigation of these latexes by preparative thin layer chromatography (PTLC) afforded two anthrones, which were identified as aloin A/B and microdontin A/B on the basis of NMR and MS analysis. In the present study, in vivo anti-inflammatory activities of the leaf latexes of A. adigratana and A. elegans as well as the two isolated anthrones were evaluated using carrageenan-induced mouse paw oedema model. It was noted that the latexes as well as the isolated compounds possess anti-inflammatory activities in a dose-dependent manner. The results also showed that microdontin A/B has a better activity than aloin A/B, in both the early and late phases of inflammation. At a tested dose of 200 mg/kg, microdontin A/B showed oedema inhibition of 35.9%, one h after carrageenan injection, while the inhibition caused by the standard drug indomethacin (10 mg/kg) was 18.6%. In conclusion, the results of the present work confirmed that A. adigratana and A. elegans have genuine anti-inflammatory activities attributed at least in part to the presence of aloin A/B and microdontin A/B in the leaves supporting their use in traditional medicine. Keywords: Aloe adigratana, Aloe elegans, anti-inflammatory, microdontin A/B, aloin A/B