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THERAPEUTIC BIOLOGY OF Gmelina asiatica Linn
Published in V. R. Mohan, A. Doss, P. S. Tresina, Ethnomedicinal Plants with Therapeutic Properties, 2019
S. Jeeva, A. R. Florence, R. Mary Sujin
Gas chromatography–mass spectroscopy (GC–MS) analysis, nine bioactive phytochemical compounds were identified in the methanolic leaf extract of G. asiatica by Azhagumurugan and Rajan (2014). Methanol extract of heart wood powder fraction contains crystalline components such as methyl p-methoxy-cinnamate, sitosterol, paulownin, gmelinol, methyl-p-hydroxy-cinnamate, and cycloolivil lignans (Anjaneyulu et al., 1975). The phytoconstituents isolated from the G. asiatica roots contain (+) sesamin, (-) pinoresinol, (-) piperitol, sakuranetin, ovalifolin (Satyanarayana et al., 2007; Balijepalli et al., 2010), and nitidine (Gakunju et al., 1995). Triglycerides (10.1%) and 2-monoglycerides (1.6%) were recovered by thin-layer chromatographic method from G. asiatica seeds (Gunstone and Quresh, 1965).
Flavonoids as inhibitors of human neutrophil elastase
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2021
Katarzyna Jakimiuk, Jakub Gesek, Atanas G. Atanasov, Michał Tomczyk
Breviscapine, a flavonoid obtained from Erigeron breviscapus reduces NE levels associated with pulmonary inflammatory response and lung function in children undergoing open-heart surgery. A positive effect was observed in patients taking 1 mg/kg or 0.5 mg/kg breviscapine103. Compounds isolated from the ethyl acetate extract of Scorzonera latifolia were also selected for further investigation of their inhibitory effect. Quercetin 3-O-β-apiofuranosyl-(1‴→2″)-β-d-glucoside and 7-methylisoorientin display anti-elastase activities of 30.16% and 28.60%, respectively104. Phloretin obtained from Malus doumeri var. formosana has been shown to inhibit elastase in a concentration-dependent manner. At concentrations of 36.5–366 µM, 51.8–77.3% enzyme inhibition was observed105,106. The flavonone sakuranetin at a concentration of 100 µM reduces the release of elastase by 60%107. In a different study, sakuranetin was applied in an in vivo mouse model and did not show adverse clinical effects in preventing elastase-induced emphysema108. A 7-O-methylaromadendrin isolated from Inula viscosa decreased elastase production by 50% at 100 µM107. Glycitin was also evaluated for its NE release inhibitory properties, and the results revealed that a compound at 10 µM lowered enzyme activity109. 5-O-demethylnobiletin, a polymethoxyflavone isolated from Sideritis tragoriganum, inhibited elastase release by 48% at 10 µM. It is worth mentioning that the described flavonoids did not affect the activity of this enzyme110. The results of the elastase assays showed that at a concentration of 100 µM, naringenin, liquiritigenin, quercetin, apigenin, and sulfuretin possess inhibitory activities of 39%, 52%, 65%, 57%, and 38%, respectively111. The elastase inhibitory activities of the isolated compounds from the EtOAc (ethyl acetate) subextract of Epilobium angustifolium were also evaluated. Hyperoside, kaempferol, kaempferol 3-O-α-l-rhamnoside, quercetin 3-O-α-l-rhamnoside, and quercetin 3-O-α-l-arabinoside at a concentration of 100 µg/mL revealed inhibitory potentials of 19.87%, 15.33%, 9.76%, 8.92%, and 7.08%, respectively112.
In vitro α-glucosidase inhibition by Brazilian medicinal plant extracts characterised by ultra-high performance liquid chromatography coupled to mass spectrometry
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2022
Mariacaterina Lianza, Ferruccio Poli, Alan Menezes do Nascimento, Aline Soares da Silva, Thamirys Silva da Fonseca, Marcos Vinicius Toledo, Rosineide Costa Simas, Andréa Rodrigues Chaves, Gilda Guimarães Leitão, Suzana Guimarães Leitão
From UHPLC-ESI-MS/MS analysis, the chemical composition of the two extracts from the leaves of L. origanoides resulted slightly different (Table 2). The extract from Manaus (LOM) showed more abundant presence of C-glycosyl flavones. Isoorientin and isovitexin, possessing the highest relative percentage, were not detected in the leaves extract from Videiras Valley (LOVV). Both compounds were successfully tested against α-glucosidase enzyme, resulting potent inhibitors37. Vicenin 2 was detected in both extracts. This C-glycosyl flavone was proved to be a multitarget agent for treatment of diabetes and relative complications. In addition to inhibiting the α-glucosidase enzyme, it resulted active against the rat lens aldose reductase and the protein tyrosine phosphatase, two enzymes involved in the modulation of insulin sensitivity and in the conversion of glucose into sorbitol, respectively38. Moreover, its interaction against the enzyme was described by a docking study, where vicenin 2 showed a docking score lower than isoorientin and isovitexin39. Some compounds detected in LOVV were not found in LOM. These metabolites were pinocembrin, sakuranetin, genkwanin, aromadendrin, and homoeriodictyol. Considering the relative percentages of the detected compounds, the LOVV extract resulted mostly composed by sakuranetin, vicenin 2, naringenin, and pinocembrin. Among these, vicenin 2, naringenin, and pinocembrin are promising α-glucosidase inhibitors40,41, while sakuranetin has been found to possess only a moderate activity against the enzyme42. These differences in the phytochemical profiles of the two extracts, which resulted in a different bioactivity, are certainly due to the different environment where the plants grew. Altitude, solar irradiation, supply of water and soil type strongly influence the production of flavonoids and the activation of certain biosynthetic pathways rather than others43,44. L. origanoides (LOVV) extract was fractioned into nine fractions which were tested at the concentration of 100 µg/mL (Table S3), that is close to the IC50 of the extract (94.24 ± 2.1 µg/mL). Considering this, only the fractions with inhibition greater than 60% were considered for the calculation of IC50, namely F05 and F08. The most active fraction F08, showing an IC50 value of 15.9 μg/mL, was also dereplicated by UHPLC-ESI-MS/MS analysis (Table 2). This fraction resulted mostly composed by vicenin 2 and naringenin, while sakuranetin was detected in low quantity. Fraction F05 was predominantly composed by pinocembrin, which was previously isolated from the same plant material as described by Leitão et al.31, thus, this isolated compound was used as standard for the identification.