Isomahanine

J Agric Food Chem. 2003 Oct 22;51(22):6461-7.

Comparison of antioxidative properties of carbazole alkaloids from Murraya koenigii leaves.[Pubmed: 14558763]

METHODS AND RESULTS:
A new dimeric carbazole alkaloid, 8,10'-[3,3',11,11'-tetrahydro-9,9'-dihydroxy-3,3',5,8'-tetramethyl-3,3'-bis(4-methyl-3-pentenyl)]bipyrano[3,2-a]carbazole (12), was isolated from the CH(2)Cl(2) extract of Murraya koenigii together with six known carbazole alkaloids, koenimbine (6), O-methylmurrayamine A (7), O-methylmahanine (8), Isomahanine (9), bismahanine (10), and bispyrayafoline (11). Their structures were determined on the basis of (1)H and (13)C NMR spectroscopic and mass spectrometric (MS) data. The antioxidative properties of 12 carbazole alkaloids isolated from leaves of M. koenigii were evaluated on the basis of the oil stability index together with their radical scavenging ability against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. On the basis of the lag time to reach a steady state, the 12 carbazoles were classified into three groups.
CONCLUSIONS:
It is suggested that an aryl hydroxyl substituent on the carbazole rings plays a role in stabilizing the thermal oxidation and rate of reaction against DPPH radical.

J. Agr. Chem. Env., 2013, 02(4):90-100.

Antibacterial compounds from Rutaceae with activities against Flavobacterium columnare and Streptococcus iniae[Reference: WebLink]

METHODS AND RESULTS:
From the ethyl acetate extract of Murraya koenegii (Rutaceae) leaves, Isomahanine (1) and mahanine (2) were isolated that showed antibacterial activity towards Flavobacterium columnare and Streptococcus iniae which caused columnaris disease and streptococcosis respectively. Isomahanine was found to have the strongest activity against F. columnare (isolate ALM-00-173) and S. iniae (isolate LA94-426) based on 24-h 50% inhibition concentration (IC50) and minimum inhibition concentration (MIC). Although compound (7), a nicotinamide isolated from Amyris texana had the lowest MIC (2.8 ± 0 mg/L) of any of the test compounds against F. columnare, the 24-h IC50 of 14.8 ± 0.6 mg/L was higher than that of Isomahanine and subsequently the 24-h IC50 RDC values for (7) were almost a magnitude of order higher than those obtained for Isomahanine.
CONCLUSIONS:
Isomahanine also had the strongest activity against S. iniae, with a 24-h IC50 of 1.3 ± 0.1 mg/L and MIC of 3.5 ± 0 mg/L, respectively.

J. Enzym. Inhib. Med. Ch., 2015:1-5.

Inhibition of soluble epoxide hydrolase activity by compounds isolated from the aerial parts of Glycosmis stenocarpa.[Reference: WebLink]

METHODS AND RESULTS:
The aim of this study is to search for soluble epoxide hydrolase (sEH) inhibitors from natural plants, bioassay-guided fractionation of lipophilic n-hexane and chloroform layers of an extract of the aerial parts of Glycosmis stenocarpa led to the isolation of 12 compounds (1-12) including murrayafoline-A (1), Isomahanine (2), bisIsomahanine (3), saropeptate (4), (24 S)-ergost-4-en-3,6-dione (5), stigmasta-4-en-3,6-dion (6), stigmast-4-en-3-one (7), β-sitosterol (8), 24-methylpollinastanol (9), trans-phytol (10), neosarmentol III (11) and (+)-epiloliolide (12). Their structures were elucidated on the basis of spectroscopic data. Among them, neosarmentol III (11) was isolated from nature for the first time. All the isolated compounds were evaluated for their inhibitory activity against sEH.
CONCLUSIONS:
Among isolated carbazole-type compounds, Isomahanine (2) and bisIsomahanine (3) were identified as a potent inhibitor of sEH, with IC50 values of 22.5 ± 1.7 and 7.7 ± 1.2 µM, respectively. Moreover, the inhibitory action of 2 and 3 represented mixed-type enzyme inhibition.