Anti-Mycobacterium tuberculosis activity of essential oil and 6,7-dehydroroyleanone isolated from leaves of Tetradenia riparia (Hochst.) Codd (Lamiaceae).
BACKGROUND
The global resurgence of tuberculosis (TB) and the development of drug resistance, as multidrug-resistant (MDR) and extensively drug-resistant (XDR) Mycobacterium tuberculosis isolates, are a threat to TB control and have created a need for new and more effective anti-TB drugs.


AIM
The current study evaluated the in vitro cytotoxicity and activity of Tetradenia riparia essential oil (TrEO) and 6,7-dehydroroyleanone pure compound against M. tuberculosis H37Rv and susceptible and resistant clinical isolates.


METHODS
The in vitro activities of TrEO and 6,7-dehydroroyleanone were determined by Resazurin Microtiter Assay Plate (REMA). The cytotoxicity was evaluated in murine peritoneal macrophages by Alamar Blue assay. The cytotoxic effects were expressed as median concentration cytotoxicity (CC50) and the selectivity index (SI) was calculated.


RESULTS
TrEO and 6,7-dehydroroyleanone showed activity against M. tuberculosis H37Rv with minimum inhibitory concentration (MIC) 62.5 µg/ml and 31.2 µg/ml, respectively. Both of them exhibited activities against resistant and susceptible M. tuberculosis clinical isolates with MIC values between 31.2 and 62.5 µg/ml. Cytotoxicity assays showed SI 1.9 and 7.9 for TrEO and 6,7-dehydroroyleanone, respectively.


CONCLUSION
These results revealed that TrEO isolated from leaves of T. riparia and the pure compound 6,7-dehydroroyleanone display good activity against M. tuberculosis clinical isolates, including MDR isolates, with low cytotoxicity to murine macrophages. The 6,7-dehydroroyleanone compound is a potential candidate for anti-TB drug.
['Baldin|Vanessa Pietrowski|VP|', 'Scodro|Regiane Bertin de Lima|RBL|', 'Lopes-Ortiz|Mariana Aparecida|MA|', 'de Almeida|Aryadne Larissa|AL|', 'Gazim|Zilda Cristiani|ZC|', 'Ferarrese|Letícia|L|', 'Faiões|Viviane Dos Santos|VDS|', 'Torres-Santos|Eduardo Caio|EC|', 'Pires|Claudia Terencio Agostinho|CTA|', 'Caleffi-Ferracioli|Katiany Rizzieri|KR|', 'Siqueira|Vera Lucia Dias|VLD|', 'Cortez|Diógenes Aparício Garcia|DAG|', 'Cardoso|Rosilene Fressatti|RF|']
D045784:Abietanes D000818:Animals D000995:Antitubercular Agents D002478:Cells, Cultured D019686:Lamiaceae D017737:Macrophages, Peritoneal D051379:Mice D008826:Microbial Sensitivity Tests D009169:Mycobacterium tuberculosis D009822:Oils, Volatile D010936:Plant Extracts D018515:Plant Leaves D010938:Plant Oils
Essential oil Tetradenia riparia Mycobacterium tuberculosis Cytotoxicity Antimycobacterial activity