Phytochemicals from Polyalthia Species: Potential and Implication on Anti-Oxidant, Anti-Inflammatory, Anti-Cancer, and Chemoprevention Activities

The impact of seasonal variation on the composition of the volatile oil of Polyalthia suberosa (Roxb.) Thwaites leaves and evaluation of its acetylcholinesterase inhibitory activity

BACKGROUND

Polyalthia suberosa (Roxb.) Thwaites (Annonaceae) is a medicinal plant that has been reported for its various pharmacological potentials, such as its anti-inflammatory, analgesic, antioxidant, and neuropharmacological activities. This study aimed to analyze the leaf essential oils of P. suberosa (PSLO) collected in different seasons, to evaluate the acetylcholinesterase inhibitory activity, and to corroborate the obtained results via in-silico molecular docking studies.

METHODS

The leaf essential oils of P. suberosa collected in different seasons were analyzed separately by GC/MS. The acetylcholinesterase inhibitory activity of the leaves oil was assessed via colorimetric assay. In-silico molecular docking studies were elucidated by virtual docking of the main compounds identified in P. suberosa leaf essential oil to the active sites in human acetylcholinesterase crystal structure.

RESULTS

A total of 125 compounds were identified where D-limonene (0.07 - 24.7%), α-copaene (2.25 - 15.49%), E-β-caryophyllene (5.17 - 14.42%), 24-noroleana-3,12-diene (12.92%), β-pinene (0.14 - 8.59%), and α-humulene (2.49-6.9%) were the most abundant components. Results showed a noteworthy influence of the collection season on the chemical composition and yield of the volatile oils. The tested oil adequately inhibited acetylcholinesterase enzyme with an IC50 value of 91.94 µg/mL. Additionally, in-silico molecular docking unveiled that palmitic acid, phytol, p-cymene, and caryophyllene oxide demonstrated the highest fitting scores within the active sites of human acetylcholinesterase enzyme.

CONCLUSIONS

From these findings, it is concluded that P. suberosa leaf oil should be evaluated as a food supplement for enhancing memory.

“Malancha” [Alternanthera philoxeroides (Mart.) Griseb.]: A Potential Therapeutic Option against Viral Diseases

Alternanthera philoxeroides (Mart.) Griseb., commonly known as “Alligator weed” in English, and “Malancha” in Bengali, is a leafy vegetable from the family Amaranthaceae A. L. de Jussieu. This species is native to China, particularly to the provinces around the Yangtze River, other Far East and South-East Asian countries, and countries from other continents (e.g., South America). This plant also grows in certain areas in Australia, New Zealand, and the USA. While in Bangladesh the leaves of this plant are consumed as a vegetable, in China, this plant has been used widely as a traditional remedy for the treatment of various viral diseases (e.g., measles, influenza, and haemorrhagic fever). Flavonoids and saponins are the two largest groups of phytochemicals produced by this plant, and the antiviral property of this plant and its compounds has been studied extensively. This review article reviews all published literature on this plant and critically appraises its phytochemical profile linking to biomolecular interactions and therapeutic potential, particularly, against viral diseases.

Clerodane diterpene induces apoptosis/anoikis and suppresses migration and invasion of human bladder cancer cells through the histone deacetylases, integrin–focal adhesion kinase, and matrix metalloproteinase 9 signalling pathways

Clerodane diterpene, a class of bicyclic diterpenoids, is found in hundreds of plant species. 16-hydroxycleroda-3,13-dien-15,16-olide (CD) can be isolated from the plant Polyalthia longifolia and has been applied against oral cancer and glioma by xenograft model. In this study, we aim to explore its antitumour action by examining its histone deacetylase (HDAC) activity and integrin-associated intracellular signalling pathway on T24 human bladder cancer (BC) cells. Our results revealed that CD-inhibited colony formation, HDAC activity, HDAC (1, 2 and 3) mRNA and cell spreading on fibronectin-coated surfaces in a concentration-dependent manner. Furthermore, decreased cFLIP and increased caspase-8 cleavage accompanied CD-induced cell death. At non-toxic concentrations, CD blocked the migration and invasion of T24 cells. CD hindered migration and invasion by the downregulation of fibronectin, integrin α5 β1, β-catenin, FAK, vinculin and Rho A, as well as by reduction of phosphorylated glycogen synthase kinase 3 β (pGSK3 β), pSrc, pstat3 and pNF κB. We observed that the MMP9 gene was closely linked with prognosis of patients with bladder cancer. MMP9 protein levels and activity were largely attenuated by CD in a concentration-dependent manner. In conclusion, CD-induced caspase-8-dependent apoptosis and suppressed migration and invasion by blocking several intracellular signalling pathways, including downregulation of HDAC activity and integrin–FAK and MMP9 pathways.

Green Extraction of Bioactive Compounds from Plant Biomass and Their Application in Meat as Natural Antioxidant

Plant extracts are rich in various bioactive compounds exerting antioxidants effects, such as phenolics, catechins, flavonoids, quercetin, anthocyanin, tocopherol, rutin, chlorogenic acid, lycopene, caffeic acid, ferulic acid, p-coumaric acid, vitamin C, protocatechuic acid, vitamin E, carotenoids, β-carotene, myricetin, kaempferol, carnosine, zeaxanthin, sesamol, rosmarinic acid, carnosic acid, and carnosol. The extraction processing protocols such as solvent, time, temperature, and plant powder should be optimized to obtain the optimum yield with the maximum concentration of active ingredients. The application of novel green extraction technologies has improved extraction yields with a high concentration of active compounds, heat-labile compounds at a lower environmental cost, in a short duration, and with efficient utilization of the solvent. The application of various combinations of extraction technologies has proved to exert a synergistic effect or to act as an adjunct. There is a need for proper identification, segregation, and purification of the active ingredients in plant extracts for their efficient utilization in the meat industry, as natural antioxidants. The present review has critically analyzed the conventional and green extraction technologies in extracting bioactive compounds from plant biomass and their utilization in meat as natural antioxidants.