Isogentisin

Planta Medica,1980,39(1):19-23.

Inhibition of Type A and Type B Monoamine Oxidase by Isogentisin and its 3-O-Glucoside.[Reference: WebLink]

METHODS AND RESULTS:
Isogentisin and its 3-O-glucoside were found to inhibit monoamine oxidase (MAO) in rat brain mitochondria in vitro using 5-hydroxytryptamine (5-HT) and (3-phenylethylamine (PEA) as relatively specific substrates for type A and type B MAO, respectively. Isogentisin showed much more potent MAO inhibition than its 3-O-glucoside for both substrates. The inhibition by both compounds was fully competitive for both substrates. Both compounds were found to be almost nonselective inhibitors for type A and type B MAO. popular medicine both in Europe and Asia due to their unique actions on the central nervous system [2]. In our previous preliminary communication [3], we briefly reported that Isogentisin and its 3-O-glucoside inhibit monoamine oxidase (MAO) in vitro using kynuramine as substrate.
CONCLUSIONS:
Since mitochondrial MAO is believed to exist in many animal tissues in two functional forms called type A and type B [4-6], in the present paper we have studied MAO inhibition by Isogentisin and its 3-O-glucoside using 5-hydroxytryptamine (5-HT) and (3-phenylethylamine (PEA) as relatively specific substrates for type A and type B MAO, respectively.

Planta Medica, 2007, 73(9):871-871.

Antimicrobial activity of Gentiana lutea L. extracts and isolated compounds mangiferin, isogentisin and gentiopicrin[Reference: WebLink]

Plant material of Gentiana lutea L. was collected on the mountain Suvobor. Air-dried leaves and flowers were extracted with methanol in a Soxhlet apparatus for 24h. Evaporated dry extracts were used for experiments.
METHODS AND RESULTS:
Mangiferin (MG), Isogentisin (IG) and gentiopicrin (GP) have been isolated according to previously published procedures [1] and their structures were confirmed using UV-VIS, IR and NMR techniques. A variety of microorganisms Escherichia coli (ATCC 25922), Salmonella typhimurium (ATCC 14028), Enterobacter cloacae (ATCC 13883), Pseudomonas aeruginosa (ATCC 27853), P. tolaasii (NCTC 387), Proteus mirabilis (ATCC 14273), Staphylococcus aureus (ATCC 25923), S. epidermidis (ATCC 12228), Streptococcus faecalis (ATCC 12952), Bacillus subtilis (ATCC 6051), Micrococcus luteus (ATCC 10240), M. flavus (ATCC 14452), Sarcina lutea (ATCC 10054), Listeria monocytogenes (ATCC 15313) as well as human pathogen fungi Candida albicans were used in the antimicrobial assay. The MIC values have been determined using the broth microdilution method in 96-hole plates according to NCCLS [2]. Serial dilutions of the stock solutions of tested extracts in broth medium (Muller-Hinton broth or Sabouraud broth) were prepared in a microtiter plate. The microbial suspensions were added in the microwells at the concentration of 5×105 organisms/mL. MICs were determined as the lowest concentrations preventing visible growth. The standard antibiotic streptomycin was used to control the sensitivity of tested bacteria, whereas nystatin was used as a control against the fungi. Each assay was repeated two times. Leaves contained 9.57±0.4mg/g dw of MG, 12.86±0.7mg/g dw of IG and 38.85±0.7mg/g dw of GP while flowers contained 8.98±0.4mg/g dw of MG, 123.23±3.1mg/g dw of IG and 48.38±1.4mg/g dw of GP.
CONCLUSIONS:
Mangiferin, Isogentisin and gentiopicrin as well as extracts of leaves and flowers showed antimicrobial activity with MIC values ranging from 117–310µg/ml.

Mutation Research/Genetic Toxicology,1983,116(2): 103-117.

Mutagenic activities of gentisin and isogentisin from Gentianae radix (Gentianaceae).[Reference: WebLink]

The mutagenic activities of 2 hydroxyxanthones, gentisin and Isogentisin, obtained from the methanol extract of Gentianae radix (Gentianacea) were investigated.
METHODS AND RESULTS:
The methanol extract of Gentianae radix, which showed mutagenicity in the Ames test in Salmonella typhimurium strain TA100 with S9 mix, was fractionated by column chromatography on Sephadex LH-20, and the fractions were purified by preparative TLC and column chromatography on polyamide. 2 mutagenic materials thus obtained, S1 and S2, each gave a single band on TLC. Identification of S1 and S2 was accomplished by comparing the analytical (mps, elementary analyses) and spectral (UV, IR, mass, NMR) results for S1 and S2 with literature data for gentisin and Isogentisin. At doses below 10 μg, S1 (gentisin) and S2 (Isogentisin) had similar specific mutagenic activities. At doses of over 10 to 50 μg, the mutagenic activities of S2 and S1 were 19.1 and 6.94 revertants per μg respectively. This much lower activity of S1 than S2 may be a result of its poor solubility owing to the presence of the OMe group at C-3.
CONCLUSIONS:
The combined yield of S1 and S2 was about 76 mg (40 mg as S1 and 36 mg as S2), which accounted for 76% of the content of mutagenic compounds (100 mg) estimated roughly from the total mutagenic activity in the extract of the starting materials (100 g).