Bioassay-guided isolation and POM analyses of a new immunomodulatory polyphenolic constituent from Callistemon viridiflorus

Systematic Review of Chemical Compounds with Immunomodulatory Action Isolated from African Medicinal Plants

A robust, well-functioning immune system is the cornerstone of good health. Various factors may influence the immune system's effectiveness, potentially leading to immune system failure. This review aims to provide an overview of the structure and action of immunomodulators isolated from African medicinal plants. The research was conducted according to PRISMA guidelines. Full-text access research articles published in English up to December 2023, including plant characteristics, isolated phytochemicals, and immuno-modulatory activities, were screened. The chemical structures of the isolated compounds were generated using ChemDraw® (version 12.0.1076), and convergent and distinctive signaling pathways were highlighted. These phytochemicals with demonstrated immunostimulatory activity include alkaloids (berberine, piperine, magnoflorine), polysaccharides (pectin, glucan, acemannan, CALB-4, GMP90-1), glycosides (syringin, cordifolioside, tinocordiside, aucubin), phenolic compounds (ferulic acid, vanillic acid, eupalitin), flavonoids (curcumin, centaurein, kaempferin, luteolin, guajaverin, etc.), terpenoids (oleanolic acid, ursolic acid, betulinic acid, boswellic acids, corosolic acid, nimbidin, andrographolides). These discussed compounds exert their effects through various mechanisms, targeting the modulation of MAPKs, PI3K-Akt, and NF-kB. These mechanisms can support the traditional use of medicinal plants to treat immune-related diseases. The outcomes of this overview are to provoke structural action optimization, to orient research on particular natural chemicals for managing inflammatory, infectious diseases and cancers, or to boost vaccine immunogenicity.

Antioxidant, Anti-inflammatory and Cytotoxic Activity of Schinus terebinthifolia Fruit and Isolation of a New Immunomodulatory Polyphenolic Compound

Background:

The fruit of Schinus terebinthifolia Raddi is used in ethnomedicine for the treatment of different ailments.

Materials and Methods:

We studied the phytochemical profile of S. terebinthifolia fruit and evaluated its properties, including its antioxidant, anti-inflammatory, analgesic, cytotoxic and antimicrobial activity.

Results:

Phytochemical investigation of S. terebinthifolia fruit showed an estimated total phenolic content of 67 mg of gallic acid equivalent (GAE)/g, with respect to gallic acid, while the flavonoid content was 26 mg of quercetin equivalent (QE)/g, in terms of quercetin. Bioassay fractionation of methanolic extract of the fruit resulted in the isolation of a new molecule for the first time from this natural source: 4′,methoxy-6-vinyl-7- O-rhamnosyl-dihydromyricetin or 4′,methoxy-6-vinyl-7- O-rhamnosyl-ampelopsin (Compound 8). Seven other phenolic compounds were isolated, such as (1) gallic acid; (2) afzelin; (3) quercetin 3- O- β-D-glucopyranoside; (4) genistein 7- O- α-l-rhamnopyranoside; (5) ellagic acid; (6) kaempferol and (7) quercetin. The new compound was ascertained using UV, NMR and MS spectra and acid hydrolysis analysis. Significant antioxidant, cytotoxic, anti-inflammatory, analgesic and antimicrobial properties were observed in the alcohol extract, as well as proliferation inhibition in MCF-7 human cancer cell lines. Its activity in elevating glutathione levels in diabetic rats could be due to its anti-inflammatory and immunomodulatory properties.

Conclusion:

The new compound shows immunomodulatory effects that can be utilized to augment host responses, which is important in both cancer and infectious diseases and thus worth further pharmacological investigation.

In vitro potential antiviral SARS-CoV-19- activity of natural product thymohydroquinone and dithymoquinone from Nigella sativa

Inflammation, oxidation, and compromised immunity all increase the dangers of COVID-19, whereas many pharmaceutical protocols may lead to increased immunity such as ingesting from sources containing vitamin E and zinc. A global search for natural remedies to fight COVID-19 has emerged, to assist in the treatment of this infamous coronavirus. Nigella satvia is a world-renowned plant, an esteemed herbal remedy, which can be used as a liquid medicine to increase immunity while decreasing the dangers of acute respiratory distress syndrome. Thymoqinone (TQ), dithymoqinone (DTQ) and thymohydroquinone (THQ), are major compounds of the essential oil contained in N.sativa. A current study aims to discover the antiviral activity of two compounds, Thymohydroquinone and Dithymoquinone, which are synthesized through simple chemical procedures, deriving from thymoquinone, which happens to be a major compound of Nigella sativa. A half-maximal cytotoxic concentration, “CC50”, was calculated by MTT assay for each individual drug, The sample showed anti-SARS-CoV-2 activity at non-cytotoxic nanomolar concentrations in vitro with a low selectivity index (CC50/IC50 = 31.74/23.15 = 1.4), whereby Dimthymoquinone shows high cytotoxicity.

Pharmacophores Modeling in Terms of Prediction of Theoretical Physicochemical Properties and Verification by EXPERIMENTAL correlations of Carbacylamidophosphates (CAPh) and Sulfanylamidophosphates (SAPh) Tested as New Carbonic Anhydrase Inhibitors

Background:

The function of Carbonic anhydrase is to facilitate the physiological process i.e. interconversion of CO2 to HCO3 - by hydration. Carbonic anhydrase enzyme plays a vital role in different physiological processes to regulate pH as well as regulate the inner environment of CO2 and secretion of electrolytes.

Methods:

Six representatives of amidophosphate derivatives (L1-L6) were synthesized and evaluated for their biological activities against carbonic anhydrase enzyme.

Results:

Out of six derivatives, L1 (IC50 = 12.5 ± 1.35 µM), and L2 (IC50 = 3.12 ± 0.45 µM) showed potent activity against BCA-II. While (L3, L4 and L5) showed weak inhibitory activity with IC50 values of 24.5 ± 2.25, 55.5± 1.60, and 75.5 ± 1.25 µM, respectively and were found to be weak inhibitors of carbonic anhydrase as compared to acetazolamide (IC50 =0.12± 0.03µM), used as standard inhibitor. A computational Petra/Osiris/Molinspiration/DFT (POM/DFT) based model has been expanded for the determination of physicochemical parameters governing the bioactivity amidophosphate derivatives (L1-L6) containing (O1 --- O2) pharmacophore site. The six compounds (L1-L6) analyzed here were previously experimentally and now virtually screened for their anti-carbonic anhydrase activity.

:

A computational Petra/Osiris/Molinspiration/DFT (POM/DFT) based model has been expanded for the determination of physicochemical parameters governing the bioactivity amidophosphate derivatives (L1-L6) containing (O1 --- O2) pharmacophore site. The six compounds (L1-L6) analyzed here were previously experimentally and now virtually screened for their anti-carbonic anhydrase activity.

Conclusion:

The highest anti-carbonic anhydrase activity was obtained for compound L2, which exhibited excellent bioactivity (% of inhibition = 95%), comparable to acetazolamide (% of inhibition = 89%). The compound L3 represents increased activity as compared to its analogues (L4-L6). The increase of bioactivity from L3 to L4-L6 could be attributed to the presence of a minimum of steric effect of substituents of P=O moiety which plays a decisive template part in the organization of anti-carbonic anhydrase (O1---O2) phramacophore site. Moreover, it is inexpensive, has little side effects and possible inclusions in selective anti-carbonic anhydrase agents design.

Two new 12-membered macrolides from the endophytic fungal strain Cladosprium colocasiae A801 of Callistemon viminalis

Two new polyketide metabolites, the 12-membered macrolides 4-hydroxy-12-methyloxacyclododecane-2,5,6-trione (1) and 12-methyloxacyclododecane-2,5,6-trione (2), were isolated from the endophytic fungal strain Cladosprium colocasiae A801 of the plant Callistemon viminalis, together with five known derivatives. Their structures were fully characterized by means of detailed spectroscopic analysis for new structures, and in comparison with published data for known compounds. The antibacterial, cytotoxic, and α-glucosidase inhibitory activities of the new compounds 1 and 2 were evaluated.