Arjunetin

Phytother Res. 2004 Feb;18(2):131-4.

Arjunetin from Terminalia arjuna as an insect feeding-deterrent and growth inhibitor.[Pubmed: 15022165 ]

METHODS AND RESULTS:
Crude ethanolic extract of the stem bark of Terminalia arjuna (Combretaceae) and its three compounds namely arjunic acid, arjungenin and Arjunetin were evaluated for antifeedant, growth inhibitory and oviposition-deterrent activities against a lepidopterous insect Spilarctia obliqua. The compound Arjunetin showed highest growth inhibitory and feeding-deterrent properties with a growth inhibition (GI(50)) and feeding-inhibition (FD(50)) of 188.5 and 287.1 micro g/g diet respectively.
CONCLUSIONS:
Oviposition bioassays indicated no oviposition-deterrence in any of the compounds tested. The structure-activity relationship study indicated the importance of a glycosidation linkage in Arjunetin.

Phytomedicine. 2019 Apr;57:158-165.

Dipeptidyl peptidase IV Inhibitory activity of Terminalia arjuna attributes to its cardioprotective effects in experimental diabetes: In silico, in vitro and in vivo analyses.[Pubmed: 30668318 ]

The marketed synthetic (Dipeptidyl peptidase-IV) DPP-IV Inhibitors are expensive antidiabetic drugs and have been reported to cause unacceptable adverse effects such as pancreatitis, angioedema, thyroid and pancreatic cancers. In this scenario research to develop novel DPP-IV Inhibitors from alternative sources is the need of the hour. Terminalia arjuna, a medicinal herb with antidiabetic and cardioprotective activities may represent a natural DPP-IV Inhibitor, the DPP-IV Inhibitory activity of which may translate into demonstrable therapeutic benefits in setting of diabetes with cardiovascular co-morbidities. The study type used for the present study was an experimental (In vitro, In vivo and In silico) design.
METHODS AND RESULTS:
The DPP-IV Inhibitory, antidiabetic and cardioprotective effects of Terminalia arjuna was evaluated in the experimental model of myocardial infarction co-existing with diabetes. To determine the active principle of Terminalia arjuna responsible for DPP-IV Inhibitory activity, the crystal structure of DPP-IV was considered as receptor which was docked against Arjunetin, Arjungenin, Arjunic acid, Arjunone, Ellagic acid, Gallic acid, Sitagliptin and Vildagliptin. The binding sites as well as affinity of various active ingredients of Terminalia arjuna for DPP- IV enzyme was elucidated using in silico studies and compared to Vildagliptin. Terminalia arjuna demonstrated significant DPP-IV Inhibitory, antidiabetic (significant reduction in HbA1C) and cardioprotective effects (restoration of myocardial CPK-MB) in the experimental model of myocardial infarction co-existing with diabetes. The cardioprotective efficacy correlated to its DPP-IV Inhibitory activity. The active ingredients of Terminalia arjuna (Arjunetin, Arjungenin, Arjunic Acid Arjunone, Ellagic acid and Gallic acid) demonstrated significant inhibition of DPP-IV enzyme. Arjunic acid and Arjunone prefers the active site pocket of DPP-IV enzyme. Compounds like Arjunetin and Vildagliptin prefers to bind near the interface region of the DPP-IV as their biological active forms are homodimer. Sitagliptin binds near the α/β hydrolase domain.
CONCLUSIONS:
The DPP-IV Inhibitory activity of Terminalia arjuna was found to be comparable to Vildagliptin. The DPP-IV Inhibitory activity translated into significant cardioprotective effects in the setting of diabetes. The active ingredient of Terminalia arjuna; Arjunetin, Arjungenin, Ellagic acid and Arjunic acid showed superior DPP-IV Inhibitory activity as compared to synthetic DPP-IV inhibitors (Sitagliptin and Vildagliptin) based on results of docking studies.

Z Naturforsch C J Biosci. 2017 May 1;72(5-6):203-208.

Termiglaucescin, a new polyhydroxy triterpene glucoside from Terminalia glaucescens with antioxidant and anti-inflammatory potential.[Pubmed: 27997356 ]

METHODS AND RESULTS:
Termiglaucescin (1), a new triterpene glucoside, has been isolated from the ethyl acetate extract of the root bark of Terminalia glaucescens Planch. ex Benth, together with 11 known compounds, β-D-glucopyranosyl 2α,3β,6β-trihydroxy-23-galloylolean-12-en-28-oate (2), arjunglucoside I (3), sericoside (4), arjungenin (5), sericic acid (6), Arjunetin (7), chebuloside II (8), 3,3',4-tri-O-methylelagic acid (9), 3,3'-di-O-methylelagic acid (10), β-sitosterol (11) and stigmasterol (12). Compounds 2, 3, 7, 8 and 9 are reported from the plant for the first time.
CONCLUSIONS:
The structures of the isolated compounds were characterized by spectroscopic data interpretations, especially 1D and 2D NMR. The triterpenic isolates showed potent antioxidant and anti-inflammatory activities.