Interaction of Bioactive Compounds of Moringa oleifera Leaves with SARS-CoV-2 Proteins to Combat COVID-19 Pathogenesis: a Phytochemical and In Silico Analysis.

Novel SARS-CoV-2 claimed a large number of human lives. The main proteins for viral entry into host cells are SARS-CoV-2 spike glycoprotein (PDB ID: 6VYB) and spike receptor-binding domain bound with ACE2 (spike RBD-ACE2; PDB ID: 6M0J). Currently, specific therapies are lacking globally. This study was designed to investigate the bioactive components from Moringa oleifera leaf (MOL) extract by gas chromatography-mass spectroscopy (GC-MS) and their binding interactions with spike glycoprotein and spike RBD-ACE2 protein through computational analysis. GC-MS-based analysis unveiled the presence of thirty-seven bioactive components in MOL extract, viz. polyphenols, fatty acids, terpenes/triterpenes, phytosterols/steroids, and aliphatic hydrocarbons. These bioactive phytoconstituents showed potential binding with SARS-CoV-2 spike glycoprotein and spike RBD-ACE2 protein through the AutoDock 4.2 tool. Further by using AutoDock 4.2 and AutoDock Vina, the top sixteen hits (binding energy ≥ - 6.0 kcal/mol) were selected, and these might be considered as active biomolecules. Moreover, molecular dynamics simulation was determined by the Desmond module. Interestingly two biomolecules, namely ß-tocopherol with spike glycoprotein and ß-sitosterol with spike RBD-ACE2, displayed the best interacting complexes and low deviations during 100-ns simulation, implying their strong stability and compactness. Remarkably, both ß-tocopherol and ß-sitosterol also showed the drug- likeness with no predicted toxicity. In conclusion, these findings suggested that both compounds ß-tocopherol and ß-sitosterol may be developed as anti-SARS-CoV-2 drugs. The current findings of in silico approach need to be optimized using in vitro and clinical studies to prove the effectiveness of phytomolecules against SARS-CoV-2.

Abatement of neurobehavioral and neurochemical dysfunctions in cerebral ischemia/reperfusion injury by Tetrapleura tetraptera fruit extract.

ETHNOPHARMACOLOGICAL RELEVANCE: Tetrapleura tetraptera Taub. (family Fabaceae), is generally found in the lowland forest of tropical Africa. Its leaves and fruits are traditionally used in West Africa for the management of brain disorders. AIM OF THE STUDY: This study evaluated the effect of Tetrapleura tetraptera methanol fruit extract (TT) on bilateral common carotid artery occlusion-induced cerebral ischemia/reperfusion (I/R) injury in male Wistar rats. MATERIALS AND METHODS: Rats pretreated with TT for 7 days before a 30 min bilateral common carotid artery occlusion and reperfusion for 24 h were assessed for neurobehavioural deficits. Cortical, striatal and hippocampal oxidative stress, pro-inflammatory events, electrolyte imbalance and neurochemical dysfunctions, as well as hippocampal histopathological alterations, were also evaluated. HPLC-DAD analysis was performed to identify likely compounds contributing to the bioactivity of the extract. RESULTS: TT reduced I/R-induced behavioral deficits and ameliorated I/R-induced oxidative stress by restoring reduced glutathione level, increasing catalase and superoxide dismutase activities, and also reducing both lipid peroxidation and xanthine oxidase activity in the brain. TT attenuated I/R-increased myeloperoxidase and lactate dehydrogenase activities as well as disturbances in Na+ and K+ levels. Alterations elicited by I/R in the activities of Na+/K+ ATPase, complex I, glutamine synthetase, acetylcholinesterase, and dopamine metabolism were abated by TT pretreatment. TT prevented I/R-induced histological changes in the hippocampus. HPLC-DAD analysis revealed the presence of aridanin, a marker compound for Tetrapleura tetraptera, and other phytochemicals. CONCLUSIONS: These findings indicate that Tetrapleura tetraptera fruit has a protective potential against stroke through modulation of redox and electrolyte imbalances, and attenuation of neurotransmitter dysregulation and other neurochemical dysfunctions. Tetrapleura tetraptera fruit could be a promising source for the discovery of bioactives for stroke therapy.

Unmodified household coffee maker assisted extraction and purification of anticancer agents from Dillenia indica fruits.

Bioassay targeted, 80% aqueous ethanol crude extract of the fruits of Dillenia indica Linn, using the unmodified household coffee maker, afforded five compounds, namely betulinic acid (1), rhamnazin (2), dillenetin (3), luteolin-7-O-ß-D-glucoside (4) and hypolaetin-8-O-ß-D-glucoside (5). The crude extract, fractions and purified compounds were tested against MDA MB-231, A549 and HeLa cancer cell lines by MTT assay, using betulinic acid 1, as a positive control. Compound 3 showed the best activity against A549 (IC50 = 26.60 ± 2.5 µM) and HeLa cancer cell lines (IC50 =19.35 ± 0.9 µM), whereas compound 5 was found to show the best activity against MDA MB-231 (IC50 = 34.62 ± 5.2µM) cancer cell line. These highly potent anticancer compounds obtained from the fruits of D. indica may be suitable for herbal drug development and formulations.

In vitro and in vivo antidiabetic effect of extracts of Melia azedarach, Zanthoxylum alatum, and Tanacetum nubigenum.

BACKGROUND: To investigate the antidiabetic effect of Himalayan Medicinal plants from India viz. Melia azedarach (Family: Meliaceae), Zanthoxylum alatum (Family: Rutaceae), Tanacetum nubigenum (Family: Asteraceae) using in-vitro as well as in-vivo approaches. METHODS: Their effects were examined on stimulation of glucose uptake by C2C12 cultured cell line, inhibitory effect on human recombinant Protein tyrosine phosphatase-1B (PTP-1B) and followed by the hypoglycaemic activity of extracts in Streptozotocin (STZ) induced diabetic rats. RESULTS: All prepared extracts had been found to enrich with polyphenolic, flavonoids, terpenoids, anthraquinones and saponins type of compounds. n-Butanol fraction of Zanthoxylum alatum showed maximum PTP-1B inhibition (61.9%) whereas ethanol extract of Tanacetum nubigenum showed strong stimulation of glucose uptake (+61.2%) in C2Cl2 myotubes. In STZ induced Sprague-Dawley rats, significant decrease in blood glucose level was observed in ethanol extract of Melia azaderach treated group as 14.8% (p < 0.01) whereas in the ethanol extract of Tanacetum nubigenum treated group, it was observed as 15.5% (p < 0.01) compare to metformin which showed 26.8% (p < 0.01) lowering of blood glucose in the same time duration of 5 h study. CONCLUSION: This study demonstrated that these plants have a significant therapeutic value in type-2-diabetes mellitus and related complications thus supporting their traditional uses in Indian traditional system of medicine.

Osteogenic activity of natural diterpenoids isolated from Cupressus sempervirens fruits in calvarial derived osteoblast cells via differentiation and mineralization.

The aim of the present study was to investigate the antiosteoporotic activity of four structurally related diterpenoids: sugiol (1), trans-communic acid (2), 15-acetoxy imbricatolic acid (3) and imbricatolic acid (4). Their osteogenic effect was evaluated by using validated models including alkaline phosphatase (ALP) assay, mineralization assay and expression of osteogenic genes-bone morphogenetic protein-2 (BMP-2) and osteoblast transcription factor (RUNX2) - in primary calvarial cultures harvested from neonatal mice. Among them, compound 1 at a dose of 1.0 mg/kg body weight exhibited significant osteoprotective effects and did not show uterine estrogenicity at the same dose. Additionally, compound 1 treatment led to improved biomechanical properties as exhibited by increased power, energy and stiffness in femoral bones compared to untreated Ovx animals. Since osteoporotic compression fracture correlates with the mechanical characteristics of trabecular bone, so that it could effectively reduce the risk of this type of fracture by improving trabecular micro architecture in postmenopausal women. Therefore, our findings proposed that diterpenoids may be useful new chemical agents in the treatment of diseases associated with bone loss.

Bioactivity-guided chemical analysis of Melia azedarach L. (Meliaceae), displaying antidiabetic activity.

One new Euphane-type triterpenoid 3ß-hydroxytirucalla-5, 24-dien-21-oic acid (1), and ten known compounds (2-11) were isolated from Melia azedarach L. through bioassay-guided chemical analysis. The structures of the isolated compounds were established by means of 1D and 2D NMR spectroscopic ((1)H, (13)C, DEPT, COSY, HSQC and HMBC) and MS spectral analyses. All the fractions and isolated pure compounds were evaluated for antidiabetic activity by determining their inhibitory effects on PTP-1B enzyme as well as glucose uptake stimulation in C2Cl2 myoblasts cells. Compounds 4 and 7 showed significant in vitro PTP-1B inhibitory activity with 69.2 and 66.8% inhibition at 10 µg/ml concentrations respectively.

Analysis of constituents of the eastern Nigeria mistletoe, Loranthus micranthus linn revealed presence of new classes of osteogenic compounds.

ETHNOPHARMACOLOGICAL RELEVANCE: Mistletoe extracts (decoctions) are used traditionally in eastern Nigeria for the management of bone pain, post menopausal syndrome and diabetes amongst several other ailments. While scientific evidence supporting its folkloric use as an antidiabetic agent has been documented, the age-long practice of its use in treatment of post menopausal syndrome has not been scientifically validated. Postmenopausal osteoporosis accounts for one of the prevalent disease conditions in aging population globally. This situation is exacerbated by the lack of osteogenic therapy. In search for plants of Nigerian origin with osteogenic potential, we evaluated eastern Nigerian mistletoe, having ethnotraditional claims of anti-diabetic, anti-hypertensive and anti-cancer activities as well as preventive effect in various post-menopausal syndromes. MATERIALS AND METHODS: Methanolic extracts of mistletoe leaves harvested from three host tress - Kola acuminata (KM), Citrus spp (CM) and Garcinia kola (GKM) - were evaluated for osteoblast viability and osteogenic activities using primary rat calvaria culture. Lupeol (1) was isolated from the stem bark of Bombax ciba and its congener, dihydoxylupeol palmitate (2) in addition to three other compounds; 3-methoxy quercetin (3), 3,4,5-trimethoxy gallate (4), and friedelin (5) were isolated from the leaves of mistletoes species. Following their chemical characterization, the compounds were evaluated for osteogenic potential using validated models including alkaline phosphatase (ALP) assay, mineralization assay and expression of osteogenic genes - bone morphogenetic protein-2 (BMP2) and osteoblast transcription factor (RUNX2) - in primary calvarial cultures harvested from neonatal rats. Uterine estrogenicity of the extracts was tested in adult female Sprague Dawley rats. RESULTS: Methanol extracts of mistletoe from three hosts exhibited increase in ALP activity (a marker of osteoblast differentiation) at lower concentrations (0.2-0.8 µg/ml) and either no or inhibitory effect at higher concentrations (1.6 and 3.2 µg/ml). None of the extract had cytotoxicity to osteoblasts at the concentrations tested. Five compounds viz. 1 from Bombax ciba, and 2-5 were isolated from the mistletoe leaves. Out of these, 5 exhibited significant loss of osteoblast viability and hence it was not considered further. All four compounds exhibited stimulatory effects on osteoblast differentiation as assessed by ALP assay and determination of osteogenic gene expression. Compound 2 was relatively more potent than its precursor, compound 1 in stimulating BMP2 upregulation. KM did not show uterine estrogenicity. CONCLUSION: Methanolic extracts from the three mistletoes species possess in vitro osteogenic activity, and from these extracts three new classes of compounds have been found to promote osteoblast differentiation in vitro. In light of these findings, we propose that mistletoe species may be developed as safer alternative(s) in the management of diseases where lack of bone formation is the pathology.

Bioactive flavanoids from Glycosmis arborea.

BACKGROUND: Glycosmis is a genus of evergreen glabrous shrub and distributed all over India. It possesses various medicinal properties and is used in indigenous medicine for cough, rheumatism, anemia, and jaundice. Glycosmis arborea is a rich source of alkaloids, terpenoids, coumarins, as well as flavonoids. RESULTS: The chemical investigation of methanol fraction of the leaves of G. arborea led to the isolation of one new flavone C-glycoside along with three known flavanoids, named as 5,7-dihydroxy-2-[4-hydroxy-3-(methoxy methyl) phenyl]-6-C-ß-d-glucopyranosyl flavone (4), 5,7,4'-trihydroxy-3'-methoxy flavone (1), 5,4'-dihydroxy-3'-methoxy-7-O-ß-d-glucupyranosyl flavanone (2), and 5,4'-dihydroxy-3'-methoxy-7-O-(α-l-rhamnosyl-(1‴→6‴)-ß-d-glucopyranosyl) flavanone (3), respectively. The structures of all compounds were elucidated with the help of nuclear magnetic resonance spectrometry. Pure compounds and fractions were evaluated for pest antifeedant and antimicrobial activity. CONCLUSION: Four compounds were isolated from the leaves of G. arborea. Among them, compound 4 showed significant antimicrobial activity.

Chemical constituents of Kigelia pinnata twigs and their GLUT4 translocation modulatory effect in skeletal muscle cells.

Phytochemical investigation of the ethanolic extract of twigs of Kigelia pinnata DC. afforded one new iridoid 7-hydroxy eucommiol (1), and nine known compounds (2-10). The structure of compounds was elucidated by extensive spectroscopic methods, including 1D, 2D NMR experiments and MS analysis. All these compounds were evaluated for GLUT4 translocation modulatory effect in skeletal muscle cells. Four of the tested compounds 1, 5, 6 and 7 showed significant stimulation of GLUT4 translocation to cell surface in skeletal muscle cells without any adverse effect on cell viability. Effect of these four compounds was concentration-dependent and comparable to standard drug rosiglitazone. These findings indicate that constituents of K. pinnata may provide leads for the therapeutics for insulin resistance and diabetes.

Phenolic glycosides from Dodecadenia grandiflora and their glucose-6-phosphatase inhibitory activity.

Phytochemical investigation of Dodecadenia grandiflora leaves led to the isolation and identification of three phenolic glycosides, designated 1-[(4'-O-(E)-p-coumaroyl)-beta-D-glucopyranosyl]-oxy-2-phenol (1), 1-[(6'-O-(E)-p-coumaroyl)-beta-D-glucopyranosyl]-oxy-2-phenol (2) and 1-[O-beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl]-oxy-2-phenol (3), along with nine known compounds. Compounds 1, 2, 5 and 9 exhibited significant glucose-6-phosphatase inhibitory activity (63.7, 66.9, 82.9 and 85.4%) with IC(50) values of 88.5, 81.0, 51 and 50 microM respectively. On the basis of biological results, a structure-activity relationship has been discussed.

Antioxidant flavonoid glycosides from Evolvulus alsinoides.

Oxidative damage is an established outcome of chronic stress. Thus, the present study was designed to investigate the modulatory role of ethanolic extract of Evolvulus alsinoides (EA) in terms of oxidative alterations at peripheral and central level in rats subjected to chronic unpredictable stress (CUS). CUS exposure for 7 days reduced Cu, Zn superoxide dismutase and catalase activity with increase in glutathione peroxidase activity and lipid peroxidation, while decrease in reduced glutathione level in blood plasma, frontal cortex and hippocampus regions of brain. Oral administration of EA extract at 200mg/kg p.o. normalized these stress induced oxidative alterations with an efficacy similar to that of melatonin. Further, EA extract was taken up for detailed chemical investigation. Two new flavonol-4'-glycoside, kaempferol 4'-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside (3) and kaempferol 4'-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (5) were isolated, along with eight known compounds (1, 2, 4 and 6-10). The structures of new compounds were established by detailed spectroscopic studies, while known compounds were characterized by direct comparison of their reported NMR data. All these compounds were evaluated for their in vitro antioxidant activity. Compounds 3, 5, 9 and 10 at 100 and 200 microg/ml showed significant in vitro antioxidant activity. Therefore, EA may hold great potential in preventing clinical deterioration in stress induced oxidative load and related disorders.