A New Macrolactone, Racemolide Along With Seven Known Compounds With Biological Activities From Mangrove Plant, Lumnitzera racemosa

One new macrolide, racemolide (1), was isolated from an MeOH extract of the leaves of Lumnitzera racemosa with 7 known compounds (2-8) by various chromatographic techniques via silica gel, octadecylsilyl column chromatography and high-performance liquid chromatography. The structure of the new compound was determined through a combination of spectroscopic and chemical analyses. The isolated compounds were evaluated for their antileishmanial, hepatoprotective, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities. Compound 1 showed potent antileishmanial activity at inhibition % value of 67.6 ± 1.24% compared with the clinical drug miltefosine (93.3 ± 4.39%). Compounds 1 and 5 possessed moderate hepatoprotective activity against acetaminophen (APAP)-induced hepatotoxicity using human HepG2 cells at protection % value of 21.70 ± 1.97% and 27.5 ± 1.41%, respectively, compared with the standard glycyrrhizin (69.50 ± 3.53%). Compounds 4, 6, 7, and 8 had high DPPH radical scavenging activity (91.10 ± 4.25, 91.53 ± 0.05, 91.91 ± 0.09, and 86.48 ± 2.87%, respectively), while compounds 3 and 5 showed moderate (45.38 ± 3.62% and 62.20 ± 1.47%, respectively), comparable with the standard trolox (89.21 ± 5.88%). These results suggest that the new compound, racemolide (1), and known compounds (3-8) are valuable as promising antileishmanial, hepatoprotective, and anti-oxidant agents