Receptor Tyrosine Kinases and Their Signaling Pathways as Therapeutic Targets of Curcumin in Cancer.

Receptor tyrosine kinases (RTKs) are transmembrane cell-surface proteins that act as signal transducers. They regulate essential cellular processes like proliferation, apoptosis, differentiation and metabolism. RTK alteration occurs in a broad spectrum of cancers, emphasising its crucial role in cancer progression and as a suitable therapeutic target. The use of small molecule RTK inhibitors however, has been crippled by the emergence of resistance, highlighting the need for a pleiotropic anti-cancer agent that can replace or be used in combination with existing pharmacological agents to enhance treatment efficacy. Curcumin is an attractive therapeutic agent mainly due to its potent anti-cancer effects, extensive range of targets and minimal toxicity. Out of the numerous documented targets of curcumin, RTKs appear to be one of the main nodes of curcumin-mediated inhibition. Many studies have found that curcumin influences RTK activation and their downstream signaling pathways resulting in increased apoptosis, decreased proliferation and decreased migration in cancer both in vitro and in vivo. This review focused on how curcumin exhibits anti-cancer effects through inhibition of RTKs and downstream signaling pathways like the MAPK, PI3K/Akt, JAK/STAT, and NF-κB pathways. Combination studies of curcumin and RTK inhibitors were also analysed with emphasis on their common molecular targets.

Phytopharmacological Evaluation of Different Solvent Extract/Fractions From Sphaeranthus indicus L. Flowers: From Traditional Therapies to Bioactive Compounds.

Sphaeranthus indicus L. is a medicinal herb having widespread traditional uses for treating common ailments. The present research work aims to explore the in-depth phytochemical composition and in vitro reactivity of six different polarity solvents (methanol, n-hexane, benzene, chloroform, ethyl acetate, and n-butanol) extracts/fractions of S. indicus flowers. The phytochemical composition was accomplished by determining total bioactive contents, HPLC-PDA polyphenolic quantification, and UHPLC-MS secondary metabolomics. The reactivity of the phenolic compounds was tested through the following biochemical assays: antioxidant (DPPH, ABTS, FRAP, CUPRAC, phosphomolybdenum, and metal chelation) and enzyme inhibition (AChE, BChE, α-glucosidase, α-amylase, urease, and tyrosinase) assays were performed. The methanol extract showed the highest values for phenolic (94.07 mg GAE/g extract) and flavonoid (78.7 mg QE/g extract) contents and was also the most active for α-glucosidase inhibition as well as radical scavenging and reducing power potential. HPLC-PDA analysis quantified rutin, naringenin, chlorogenic acid, 3-hydroxybenzoic acid, gallic acid, and epicatechin in a significant amount. UHPLC-MS analysis of methanol and ethyl acetate extracts revealed the presence of well-known phytocompounds; most of these were phenolic, flavonoid, and glycoside derivatives. The ethyl acetate fraction exhibited the highest inhibition against tyrosinase and urease, while the n-hexane fraction was most active for α-amylase. Moreover, principal component analysis highlighted the positive correlation between bioactive compounds and the tested extracts. Overall, S. indicus flower extracts were found to contain important phytochemicals, hence could be further explored to discover novel bioactive compounds that could be a valid starting point for future pharmaceutical and nutraceuticals applications.

Investigation into the biological properties, secondary metabolites composition, and toxicity of aerial and root parts of Capparis spinosa L.: An important medicinal food plant.

Capparis spinose L. also known as Caper is of great significance as a traditional medicinal food plant. The present work was targeted on the determination of chemical composition, pharmacological properties, and in-vitro toxicity of methanol and dichloromethane (DCM) extracts of different parts of C. spinosa. Chemical composition was established by determining total bioactive contents and via UHPLC-MS secondary metabolites profiling. For determination of biological activities, antioxidant capacity was determined through DPPH, ABTS, CUPRAC, FRAP, phosphomolybdenum, and metal chelating assays while enzyme inhibition against cholinesterase, tyrosinase, α-amylase and α-glucosidase were also tested. All the extracts were also tested for toxicity against two breast cell lines. The methanolic extracts were found to contain highest total phenolic and flavonoids which is correlated with their significant radical scavenging, cholinesterase, tyrosinase and glucosidase inhibition potential. Whereas DCM extracts showed significant activity for reducing power, phosphomolybdenum, metal chelation, tyrosinase, and α-amylase inhibition activities. The secondary metabolites profiling of both methanolic extracts exposed the presence of 21 different secondary metabolites belonging to glucosinolate, alkaloid, flavonoid, phenol, triterpene, and alkaloid derivatives. The present results tend to validate folklore uses of C. spinose and indicate this plant to be used as a potent source of designing novel bioactive compounds.

A scaffolded approach to unearth potential antibacterial components from epicarp of Malaysian Nephelium lappaceum L.

The emergence and spread of antimicrobial resistance have been of serious concern to human health and the management of bacterial infectious diseases. Effective treatment of these diseases requires the development of novel therapeutics, preferably free of side effects. In this regard, natural products are frequently conceived to be potential alternative sources for novel antibacterial compounds. Herein, we have evaluated the antibacterial activity of the epicarp extracts of the Malaysian cultivar of yellow rambutan fruit (Nephelium lappaceum L.) against six pathogens namely, Bacillus subtilis, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Pseudomonas aeruginosa, Klebsiella pneumoniae and Salmonella enterica. Among a series of solvent extracts, fractions of ethyl acetate and acetone have revealed significant activity towards all tested strains. Chemical profiling of these fractions, via HPLC, LC-MS and GC-MS, has generated a library of potentially bioactive compounds. Downstream virtual screening, pharmacological prediction, and receptor-ligand molecular dynamics simulation have eventually unveiled novel potential antibacterial compounds, which can be extracted for medicinal use. We report compounds like catechin, eplerenone and oritin-4-beta-ol to be computationally inhibiting the ATP-binding domain of the chaperone, DnaK of P. aeruginosa and MRSA. Thus, our work follows the objective to propose new antimicrobials capable of perforating the barrier of resistance posed by both the gram positives and the negatives.

Pharmacological, phytochemical and in-vivo toxicological perspectives of a xero-halophyte medicinal plant: Zaleya pentandra (L.) Jeffrey.

This study endeavours to investigate the phytochemical composition, biological properties and in vivo toxicity of methanol and dichloromethane extracts of Zaleya pentandra (L.) Jeffrey. Total bioactive contents, antioxidant (phosphomolybdenum and metal chelating, DPPH, ABTS, FRAP and CUPRAC) and enzyme inhibition (cholinesterases, tyrosinase α-amylase, and α-glucosidase) potential were assessed utilizing in vitro bioassays. UHPLC-MS phytochemical profiling was carried out to identify the essential compounds. The methanol extract was found to contain highest phenolic (22.60 mg GAE/g) and flavonoid (31.49 mg QE/g) contents which correlate with its most significant radical scavenging, reducing potential and tyrosinase inhibition. The dichloromethane extract was most potent for phosphomolybdenum, ferrous chelation, α-amylase, α-glucosidase, and cholinesterase inhibition assays. UHPLC-MS analysis of methanol extract unveiled to identify 11 secondary metabolites belonging to five sub-groups, i.e., phenolic, alkaloid, carbohydrate, terpenoid, and fatty acid derivatives. Additionally, in vivo toxicity was conducted for 21 days and the methanol extract at different doses (150, 200, 250 and 300 mg/kg) was administered in experimental chicks divided into five groups each containing five individuals. Different physical, haematological and biochemical parameters along with the absolute and relative weight of visceral body organs were studied. Overall, no toxic effect was noted for the extract at tested doses.