Chemical Composition and Biological Evaluation of Typha domingensis Pers. to Ameliorate Health Pathologies: In Vitro and In Silico Approaches

Human diseases are becoming more prevalent, necessitating the development of modalities to overcome the challenges of treating various disorders. In the current research, we analyzed the biomedicinal role of Typha domingensis which is an important medicinal plant. The species is traditionally used in the treatment of neurological disorders and skin malignancies. The chloroform (CFTD) and n-butanol fractions of T. domingensis (BFTD) were subjected to chemical profiling through the determination of total polyphenolic contents and GC-MS analysis. The oral toxicity test was applied to investigate the toxicity of the extracts. Antioxidant capacity was analyzed by four in vitro methods: DPPH, ABTS, FRAP, and CUPRAC. The pharmacological potential was evaluated through clinically significant enzyme inhibition assays, thrombolytic, and antimicrobial activities. In silico molecular docking approach was applied to confirm the role of T. domingensis against the enzymes. The polyphenolic quantification revealed that the BFTD was comparatively rich in total phenolic and flavonoid contents (97.14 milligrams gallic acid equivalent (mg GAE/g) and 362.5 milligrams quercetin equivalent per gram of dry extract (mg QE/g DE), respectively), as compared to the CFTD. The GC-MS analysis of the CFTD and BFTD resulted in the tentative identification of 67 and 29 compounds, respectively, with the major components of fatty acids and essential oil. The oral toxicity test revealed the safety and biocompatibility of CFTD and BFTD. Both the fractions showed promising antioxidant activity. Tyrosinase was found as the major enzyme inhibited by BFTD (78.67%) and CFTD (68.09%), whereas the standard kojic acid showed 85.58% inhibition. The inhibition results of acetylcholinesterase and butyrylcholinesterase by BFTD (71.65 and 60.79%, respectively) are higher than CFTD. Both the fractions were found active against various strains of bacteria. Furthermore, the molecular docking studies of the compounds showed a good docking score against all the docked enzymes among which deoxycaesaldekarin C was found with the highest binding affinities in comparison to the standard. The current study suggests that T. domingensis is nontoxic and can be a potential source of phytoconstituents with promising pharmacological potential.

New sesquiterpene dilactone and β-carboline alkaloid and the α-glucosidase inhibitory activity of selected phytochemicals from Neolitsea cassia (L.) Kosterm

One new sesquiterpene dilactone, coccinine (1) and one new β-carboline alkaloid, daibucarboline F (2) together with 10 known compounds; linderane (3), linderalactone (4), pseudoneolinderane (5), linderanlide C (6), linderanine A (7), epicatechin (8), (-)-taxifolin (9), astilbin (10), L-quercitrin (11) and afzelin (12) were isolated from the stems and leaves of Neolitsea cassia (L.) Kosterm (Lauraceae). The structures of (1 and 2) were established by extensive spectroscopic methods and the known compounds were identified by comparisons with data reported in literature. The relative stereochemistry of compound (1) was assigned by X-ray diffraction analysis with Cu-Kα irradiation. Compounds (3-8) and (10) were evaluated for their α-glucosidase enzymatic inhibitory activity. Compounds (4-6), (8) and (10) exhibited inhibition towards α-glucosidase enzymatic activity with IC₅₀ values ranging from 12.10 to 96.77 μM. This is the first report on the isolation of phytochemicals from N. cassia and their bioactivities.

Characteristics of proanthocyanidins in leaves of Chamaecyparis obtusa var. formosana as strong α-glucosidase inhibitors

BACKGROUND

In recent decades, there has been a growing demand for natural products with a view to using them as α-glucosidase inhibitors for reducing postprandial hyperglycemia. In this study, the hot water extract (HWE) from Chamaecyparis obtusa var. formosana (Hayata) Rehder (Cupressaceae) leaves and its soluble fractions were screened for α-glucosidase inhibition properties. The n-butanol-soluble fraction of HWE was further fractionated into 14 subfractions (B1-B14) using a Sephadex LH-20 column. The α-glucosidase-inhibitory activities and proanthocyanidin contents of all subfractions were determined. The structural characteristics of proanthocyanidins in proanthocyanidin-rich fractions were also elucidated.

RESULTS

HWE produced a dose-dependent inhibition of α-glucosidase at low dose. Its IC₅₀ value was 1.4 µg mL^-1 , showing high inhibitory activity. Subfractions B7-B14 displayed powerful α-glucosidase-inhibitory activities with IC₅₀ values ranging between 1 and 0.015 µg mL^-1 and contained abundant proanthocyanidins exceeding 300 mg g^-1 . The proanthocyanidins with higher mean degree of polymerization (mDP), higher proportions of procyanidin dimer (A1 or A2) and (epi)afzelechin of extension units and a lower proportion of epicatechin of terminal units displayed high α-glucosidase-inhibitory activities.

CONCLUSION

Proanthocyanidins in HWE were viewed as potential natural α-glucosidase inhibitors for decreasing postprandial hyperglycemia. The results indicated that specific structural characteristics of proanthocyanidins would be required for α-glucosidase-inhibitory activity. © 2018 Society of Chemical Industry.

Chemical Composition, Antibacterial and α-Glucosidase Inhibitory Activities of the Essential Oils of Neolitsea coccinea (Lauraceae)

The chemical composition, antibacterial and α-glucosidase inhibitory activities of the essential oils obtained from hydrodistillation of the fresh stem and leaf of Neolitsea coccinea B. C. Stone are reported for the first time. GC and GC-MS analysis revealed the presence of 42 volatile compounds from the stem and leaf oils, accounting for 84.9% and 90.4%, respectively of the identified components. The principle compounds in the stem oil were δ-cadinene (21.2%), 1-epi-cubenol (11.3%) and cyperotundone (10.7%), while the main compounds in the leaf oil were selin-11-en-4-α-ol (26.8%), bicyclogermacrene (12.6%), γ-eudesmol (7.1%), germacrene D (6.1%) and globulol (5.9%). The leaf oil demonstrated moderate to weak antibacterial activity towards Bacillus subtilis and Staphylococcus aureus with MIC values of 250 μg/mL and 500 μg/mL, respectively, whereas the stem oil possessed weak antibacterial activity against B. subtilis with a MIC value of 500 μg/mL. The stem and leaf oils showed significant α-glucosidase inhibitory activity with IC50 values of 32.2 ± 0.8 μg/mL and 70.9 ± 1.1 μg/mL, respectively.

Dihydropyrano [2,3-c] pyrazole: Novel in vitro inhibitors of yeast α-glucosidase

Inhibition of α-glucosidase enzyme activity is a reliable approach towards controlling post-prandial hyperglycemia associated risk factors. During the current study, a series of dihydropyrano[2,3-c] pyrazoles (1-35) were synthesized and evaluated for their α-glucosidase inhibitory activity. Compounds 1, 4, 22, 30, and 33 were found to be the potent inhibitors of the yeast α-glucosidase enzyme. Mechanistic studies on most potent compounds reveled that 1, 4, and 30 were non-competitive inhibitors (Ki=9.75±0.07, 46±0.0001, and 69.16±0.01μM, respectively), compound 22 is a competitive inhibitor (Ki=190±0.016μM), while 33 was an uncompetitive inhibitor (Ki=45±0.0014μM) of the enzyme. Finally, the cytotoxicity of potent compounds (i.e. compounds 1, 4, 22, 30, and 33) was also evaluated against mouse fibroblast 3T3 cell line assay, and no toxicity was observed. This study identifies non-cytotoxic novel inhibitors of α-glucosidase enzyme for further investigation as anti-diabetic agents.