Anti-mycobacterial activity and chemical composition of essential oils and phenolic extracts of the balsam of Liquidambar orientalis Mill. (Altingiaceae)

Abstract

Liquidambar orientalis Mill. (Altingiaceae) is known in Turkish as 'sigla' or 'gunluk' due to its gum-like exudate. Its exudate, 'balsam of Liquidambar' (BL), is of great commercial importance because it has pharmaceutical properties and is rich in essential oils and phenolics. In this study, we investigated the phenolic profile of L. orientalis. using HPLC, and 5 compounds from BL-1, (juglone, naringenin, rosmarinic acid, vanillic acid, echinacoside) and 4 compounds from BL-2 (juglone, apigenin-7-glucoside, naringenin, vanillic acid) were reported for the first time. A total of six new flavonoids (juglone, naringenin, rosmarinic acid, echinacoside, vanillic acid, and apigenin-7-glucoside) were identified from BL's by HPLC analysis. According to HPLC analyses, juglone was discovered to be the major flavonoid in both samples (BL-1 and BL-2). In addition to, naringenin, rosmarinic acid (in BL-1), and apigenin-7-glucoside (in BL-2) were found in the methanol extracts of BL. The main compounds of the essential oils of BLs were (E)-ethyl cinnamate (27.5 and 30.6%), torreyol (11.0 and 12.0%), and cinnamyl alcohol (7.2 and 7.9%). We demonstrated that BLs have antimycobacterial effectiveness against four strains of M. tuberculosis using the microplate Presto Blue assay (MPBA). Each BL showed the antimycobacterial activity against four strains of M. tuberculosis. We believe that this study will contribute to phenolic profiles, essential oils, and antimycobacterial activities of the balsam of L. orientalis.