Antioxidant constituents from Ribes glaciale Wall.: bioassay targeted in-vitro and in-silico evaluation.

Bioassay targeted phyto-investigation of dried green walnut husk of Ribes glaciale Wall. yielded one new compound as ß-D-glucopyrano (4'→3)-ß-D-glucopyranose (1) and four known compounds namely scoparone (2), apigenin (3), ß-sitosterol (4) and ß-sitosterol-D-glucoside (5). The structure of new compound was elucidated with the help of 1D, 2D and HRESIMS analysis. The antioxidant activity of extract, fractions and pure were evaluated using 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and ferric ion reducing antioxidant power (FRAP) assays that found in the following order: butanol fr. (BF) > chloroform fr. (CF) > ethylacetate fr. (EF) > Petroleum ether fr. (PF). To search for potent antioxidant agents in extract, the isolated compounds 1, 2, 3, 4 and 5 were docked on the enzyme human NADPH oxidase, lipoxygenase, cytochrome P450 and myeloperoxidase. The compound 1 was found a potent inhibitor of target enzyme revealing its high free radical scavenging potential.

Natural product-inspired synthesis of coumarin-chalcone hybrids as potential anti-breast cancer agents.

Twelve novel neo-tanshinlactone-chalcone hybrid molecules were constructed through a versatile methodology involving the Horner-Wadsworth-Emmons (HWE) olefination of 4-formyl-2H-benzo [h]chromen-2-ones and phosphonic acid diethyl esters, as the key step, and evaluated for anticancer activity against a series of four breast cancers and their related cell lines, viz. MCF-7 (ER + ve), MDA-MB-231 (ER-ve), HeLa (cervical cancer), and Ishikawa (endometrial cancer). The title compounds showed excellent to moderate in vitro anti-cancer activity in a range of 6.8-19.2 µM (IC50). Compounds 30 (IC50 = 6.8 µM and MCF-7; IC50 = 8.5 µM and MDA-MB-231) and 31 (IC50 = 14.4 µM and MCF-7; IC50 = 15.7 µM and MDA-MB-231) exhibited the best activity with compound 30 showing more potent activity than the standard drug tamoxifen. Compound 30 demonstrated a strong binding affinity with tumor necrosis factor α (TNF-α) in molecular docking studies. This is significant because TNFα is linked to MCF-7 cancer cell lines, and it enhances luminal breast cancer cell proliferation by upregulating aromatase. Additionally, virtual ADMET studies confirmed that hybrid compounds 30 and 31 met Lipinski's rule; displayed high bioavailability, excellent oral absorption, favorable albumin interactions, and strong penetration capabilities; and improved blood-brain barrier crossing. Based on the aforementioned results, compound 30 has been identified as a potential anti-breast cancer lead molecule.

Pentafuhalol-B, a Phlorotannin from Brown Algae, Strongly Inhibits the PLK-1 Overexpression in Cancer Cells as Revealed by Computational Analysis.

Polo-like kinase-1 (PLK-1) is an essential mitotic serine/threonine (Ser/Thr) kinase that belongs to the Polo-like kinase (PLK) family and is overexpressed in non-small cell lung cancer (NSCLC) via promotion of cell division. Therefore, PLK-1 may act as a promising target for the therapeutic cure of various cancers. Although a variety of anti-cancer drugs, both synthetic and naturally occurring, such as volasertib, onvansertib, thymoquinone, and quercetin, are available either alone or in combination with other therapies, they have limited efficacy, especially in the advanced stages of cancer. To the best of our knowledge, no anticancer agent has been reported from marine algae or microorganisms to date. Thus, the aim of the present study is a high-throughput virtual screening of phlorotannins, obtained from edible brown algae, using molecular docking and molecular dynamic simulation analysis. Among these, Pentafuhalol-B (PtB) showed the lowest binding energy (best of triplicate runs) against the target protein PLK-1 as compared to the reference drug volasertib. Further, in MD simulation (best of triplicate runs), the PtB-PLK-1 complex displayed stability in an implicit water system through the formation of strong molecular interactions. Additionally, MMGBSA calculation (best of triplicate runs) was also performed to validate the PtB-PLK-1 complex binding affinities and stability. Moreover, the chemical reactivity of PtB towards the PLK-1 target was also optimised using density functional theory (DFT) calculations, which exhibited a lower HOMO-LUMO energy gap. Overall, these studies suggest that PtB binds strongly within the pocket sites of PLK-1 through the formation of a stable complex, and also shows higher chemical reactivity than the reference drug volasertib. The present study demonstrated the inhibitory nature of PtB against the PLK-1 protein, establishing its potential usefulness as a small molecule inhibitor for the treatment of different types of cancer.

Immunoinformatics Strategy to Develop a Novel Universal Multiple Epitope-Based COVID-19 Vaccine.

Currently available COVID vaccines are effective in reducing mortality and severity but do not prevent transmission of the virus or reinfection by the emerging SARS-CoV-2 variants. There is an obvious need for better and longer-lasting effective vaccines for various prevailing strains and the evolving SARS-CoV-2 virus, necessitating the development of a broad-spectrum vaccine that can be used to prevent infection by reducing both the transmission rate and re-infection. During the initial phases of SARS-CoV-2 infection, the nucleocapsid (N) protein is one of the most abundantly expressed proteins. Additionally, it has been identified as the most immunogenic protein of SARS-CoV-2. In this study, state-of-the-art bioinformatics techniques have been exploited to design novel multiple epitope vaccines using conserved regions of N proteins from prevalent strains of SARS-CoV-2 for the prediction of B- and T-cell epitopes. These epitopes were sorted based on their immunogenicity, antigenicity score, and toxicity. The most effective multi-epitope construct with possible immunogenic properties was created using epitope combinations. EAAAK, AAY, and GPGPG were used as linkers to connect epitopes. The developed vaccines have shown positive results in terms of overall population coverage and stimulation of the immune response. Potential expression of the chimeric protein construct was detected after it was cloned into the Pet28a/Cas9-cys vector for expression screening in Escherichia coli. The developed vaccine performed well in computer-based immune response simulation and covered a diverse allelic population worldwide. These computational findings are very encouraging for the further testing of our candidate vaccine, which could eventually aid in the control and prevention of SARS-CoV-2 infections globally.

An ultrasound assisted, ionic liquid-molecular iodine synergy driven efficient green synthesis of pyrrolobenzodiazepine-triazole hybrids as potential anticancer agents.

Herein, we report an efficient and eco-friendly, ultrasound assisted synthetic strategy for the construction of diversified pyrrolobenzodiazepine-triazole hybrids, which are potentially pharmaceutically important scaffolds, via a domino reaction involving intermolecular electrophilic substitution followed by intramolecular Huisgen 1,3-dipolar azide-alkyne cycloaddition. The USP of the reported protocol is the use of benign and inexpensive, recyclable molecular iodine-ionic liquid synergistic catalytic system cum reaction media for achieving the synthesis. The other salient features of this method are the use of mild reaction conditions, high yield and atom economy, operational simplicity, broad substrate scope and easy workup and purification. All the synthesized compounds were evaluated for in vitro anti-proliferative activity against various cancer cell lines. From among the synthesized title compounds, 9,9-dimethyl-8-phenyl-9H-benzo [b]pyrrolo [1,2-d][1,2,3]triazolo[5,1-g][1,4]diazepine (7) was found most to be the most active compound exhibiting IC50 value of 6.60, 5.45, 7.85, 11.21, 12.24, 10.12, and 11.32 µM against MCF-7, MDA-MB-231, HeLa, SKOV-3, A549, HCT-116 and DLD-1 cell lines, respectively. Further the compounds were found to be non-toxic against normal human embryonic kidney (HEK-293) cell line.

Drug repositioning to discover novel ornithine decarboxylase inhibitors against visceral leishmaniasis.

Visceral leishmaniasis (VL) is caused by Leishmania donovani (Ld), and most cases occur in Brazil, East Africa, and India. The treatment for VL is limited and has many adverse effects. The development of safer and more efficacious drugs is urgently needed. Drug repurposing is one of the best processes to repurpose existing drugs. Ornithine decarboxylase (ODC) is an important target against L. donovani in the polyamine biosynthesis pathway. In this study, we have modeled the 3D structure of ODC and performed high-throughput virtual screening of 8630 ZINC database ligands against Leishmania donovani ornithine decarboxylase (Ld ODC), selecting 45 ligands based on their high binding score. It is further validated through molecular docking simulation and the selection of the top two lead molecules (ceftaroline fosamil and rimegepant) for Molecular Dynamics (MD) simulation, Density functional theory (DFT), and molecular mechanics generalized born surface area (MMGBSA) analysis. The results showed that the binding affinities of ceftaroline fosamil, and rimegepant are, respectively, -10.719 and 10.159 kcal/mol. The docking complexes of the two lead compounds, ceftaroline fosamil, and rimegepant, with the target ODC, were found stable during molecular dynamics simulations. Furthermore, the analysis of MMGBSA revealed that these compounds had a high binding free energy. The DFT analysis showed that the top lead molecules were more reactive than the standard drug (pentamidine). In-silico findings demonstrated that ceftaroline fosamil, and rimegepant might be recognized as potent antagonists against ODC for the treatment of VL.

Bioactive components of different nasal spray solutions may defeat SARS-Cov2: repurposing and in silico studies.

The recent outbreak "Coronavirus Disease 2019 (COVID-19)" is caused by fast-spreading and highly contagious severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). This virus enters into the human respiratory system by binding of the viral surface spike glycoprotein (S-protein) to an angiotensin-converting enzyme2 (ACE2) receptor that is found in the nasal passage and oral cavity of a human. Both spike protein and the ACE2 receptor have been identified as promising therapeutic targets to develop anti-SARS-CoV2 drugs. No therapeutic drugs have been developed as of today except for some vaccines. Therefore, potent therapeutic agents are urgently needed to combat the COVID-19 infections. This goal would be achieved only by applying drug repurposing and computational approaches. Thus, based on drug repurposing approach, we have investigated 16 bioactive components (1-16) from different nasal spray solutions to check their efficacies against human ACE2 and SARS-CoV2 spike proteins by performing molecular docking and molecular dynamic (MD) simulation studies. In this study, three bioactive components namely ciclesonide (8), levocabastine (13), and triamcinolone acetonide (16) have been found as promising inhibitory agents against SARS-CoV2 spike and human ACE2 receptor proteins with excellent binding affinities, comparing to reference drugs such as nafamostat, arbidol, losartan, and benazepril. Furthermore, MD simulations were performed (triplicate) for 100 ns to confirm the stability of 8, 13, and 16 with said protein targets and to compute MM-PBSA-based binding-free energy calculations. Thus, bioactive components 8, 13, and 16 open the door for researchers and scientist globally to investigate them against SARS-CoV2 through in vitro and in vivo analysis.

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.

Molecular Docking and Dynamics Simulation Revealed Ivermectin as Potential Drug against Schistosoma-Associated Bladder Cancer Targeting Protein Signaling: Computational Drug Repositioning Approach.

Urogenital schistosomiasis is caused by Schistosoma haematobium (S. haematobium) infection, which has been linked to the development of bladder cancer. In this study, three repurposing drugs, ivermectin, arteether and praziquantel, were screened to find the potent drug-repurposing candidate against the Schistosoma-associated bladder cancer (SABC) in humans by using computational methods. The biology of most glutathione S-transferases (GSTs) proteins and vascular endothelial growth factor (VEGF) is complex and multifaceted, according to recent evidence, and these proteins actively participate in many tumorigenic processes such as cell proliferation, cell survival and drug resistance. The VEGF and GSTs are now widely acknowledged as an important target for antitumor therapy. Thus, in this present study, ivermectin displayed promising inhibition of bladder cancer cells via targeting VEGF and GSTs signaling. Moreover, molecular docking and molecular dynamics (MD) simulation analysis revealed that ivermectin efficiently targeted the binding pockets of VEGF receptor proteins and possessed stable dynamics behavior at binding sites. Therefore, we proposed here that these compounds must be tested experimentally against VEGF and GST signaling in order to control SABC. Our study lies within the idea of discovering repurposing drugs as inhibitors against the different types of human cancers by targeting essential pathways in order to accelerate the drug development cycle.

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.

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.

Specioside (SS) & verminoside (VS) (Iridoid glycosides): isolation, characterization and comparable quantum chemical studies using density functional theory (DFT).

Two biologically important molecules specioside (SS) and verminoside (VS) have been isolated from the ethanolic extract of stem bark of Kigelia pinnata. We have explored the electronic and spectroscopic properties of these two molecules on the basis of the Density Function Theory (DFT) quantum chemical calculations along with the correlations of biological efficacies and the results are presented in this paper. The structures of the molecules were established with the help of spectroscopic techniques (1H, 13C NMR, UV-VIS, FTIR) and chemical reactivity was compared by computed DFT theory using Becke3-Lee-Yang-Parr (B3LYP)/6-31G (d,p) data basis set. UV-Visible spectrum was obtained using Time Dependent DFT method. Electric dipole moment, polarizability, first static hyper polarizability and hyper conjugative interactions were also studied with the aid of natural bond orbital (NBO) analysis of these two compounds. The thermodynamic parameters of these compounds were determined at various temperatures. The HOMO, LUMO, chemical hardness (η), chemical potential (µ), electronegativity (χ), electrophilicity power (ω), the gap energy and NBO analysis of both the compounds have been discussed in this paper. Local reactivity was evaluated through the Fukui function i.

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.

Novel Imbricatolic acid derivatives as protein tyrosine phosphatase-1B inhibitors: Design, synthesis, biological evaluation and molecular docking.

Protein tyrosine phosphatase (PTP-1B) antagonizes insulin signaling and is a potential therapeutic target for insulin resistance associated with obesity and type 2 diabetes. To find potential PTP-1B inhibitors, derivatives of Imbricatolic acid (1) have been synthesized by introducing various nitrogenous functionalities at C-15 and C-19 positions. They were evaluated for PTP-1B enzyme inhibition activity. Compounds 3, 6, 14, and 15 exhibited promising PTP-1B inhibitory activity at 10 µM concentrations with IC50 6.3, 6.8, 7.0 and 7.8 values, respectively. Structure activity relationship and molecular docking studies of these derivatives demonstrated that the integrity of the polar substituents were important for significant PTP-1B inhibitory activity. The Imbricatolic acid and active derivatives in this study might represent a starting point for development of new potential PTP-1B inhibitors.

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.

Design and synthesis of lupeol analogues and their glucose uptake stimulatory effect in L6 skeletal muscle cells.

Structure modifications of lupeol at the isopropylene moiety have been described via allylic oxidation using selenium dioxide. The antidiabetic efficacy of lupeol analogues were evaluated in vitro as glucose uptake stimulatory effect in L6 skeletal muscle cells. From all tested compounds, 2, 3, 4b and 6b showed significant stimulation of glucose uptake with respective percent stimulation of 173.1 (p <0.001), 114.1 (p <0.001), 98.3 (p <0.001) and 107.3 (p <0.001) at 10µM concentration. Stimulation of glucose uptake by these compounds is associated with enhanced translocation of glucose transporter 4 (GLUT4) and activation of IRS-1/PI3-K/AKT-dependent signaling pathway in L6 cells. Structure-activity relationship analysis of these analogues demonstrated that the integrity of α,ß-unsaturated carbonyl and acetyl moieties were important in the retention of glucose uptake stimulatory effect. It is therefore proposed that naturally occurring lupeol and their analogues might reduce blood glucose, at least in part, through stimulating glucose utilization by skeletal muscles.

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.

Synthesis of novel imbricatolic acid analogues via insertion of N-substituted piperazine at C-15/C-19 positions, displaying glucose uptake stimulation in L6 skeletal muscle cells.

A new class of N-substituted piperazine analogues of imbricatolic acid have been designed and synthesized by using the appropriate synthetic routes in excellent yield. All synthesised compounds were screened for their in vitro glucose uptake stimulatory activity. Among them compounds 4b, 4e, 8b, and 8e triggered L6 skeletal muscle cells for glucose uptake at 54.73%, 40.79%, 40.90%, and 39.55% stimulation, respectively. Compound 4b has emerged as important lead compound showing potential antidiabetic activity. Illustration about their synthesis and in vitro glucose uptake activity is described.