Herein, we report the isolation and stereo-structure of rare pyrane-based cembranoid diterpenes, 9-hydroxy-7,8-dehydro-sarcotrocheliol (1) and sarcotrocheliol (2), from Sarcophyton trocheliophorum collected from Red Sea. Absolute configurations of both compounds were revised based on single crystal X-ray analyses.

Calothamnus quadrifidus R.Br has many traditional uses and there are few reports about its chemical and biological activities. So our aim is to isolate the triterpenoidal compounds from dichloromethane fraction (DCMF) of Calothamnus quadrifidus R.Br leaves and in addition to evaluate the antibacterial activity of the isolated compounds. DCMF of C. quadrifidus leaves was subjected to different chromatographic techniques to isolate pure triterpenoidal compounds which were identified using different chemical and spectroscopic techniques. Antibacterial activities of the isolated compounds were evaluated using agar well diffusion method while minimum inhibitory concentration was assessed by microtiter plate assay method. Five compounds were isolated and they were betulinic acid (1), ursolic acid (2), 3-acetyl-23-hydroxy betulinic acid (3), 2,23-dihydroxy betulinic acid (4) and 2,21,23-trihydroxy betulinic acid (5) were isolated from DCMF of C. quadrifidus leaves for the first time. Compounds 4 and 5 showed strong antibacterial activity against S. typhimurium while compound 4, 5 and 3, 4 exhibits moderate effect against E.coli and S. aureus respectively. Pure triterpenoidal compounds isolated from C. quadrifidus leaves showed antibacterial activities in different strengths.

Natural products such as domestic herbal drugs which are easily accessible and cost-effective can be used as a complementary treatment in mild and moderate COVID-19 cases. This study aimed to detect and describe the efficiency of phenolics detected in the galangal–cinnamon mixture in the inhibition of SARS-CoV-2’s different protein targets. The potential antiviral effect of galangal–cinnamon aqueous extract (GCAE) against Low Pathogenic HCoV-229E was assessed using cytopathic effect inhibition assay and the crystal violet method. Low Pathogenic HCoV-229E was used as it is safer for in vitro laboratory experimentation and due to the conformation and the binding pockets similarity between HCoV-229E and SARS-CoV-2 M^Pro. The GCAE showed a significant antiviral effect against HCoV-229E (IC₅₀ 15.083 µg/mL). Twelve phenolic compounds were detected in the extract with ellagic, cinnamic, and gallic acids being the major identified phenolic acids, while rutin was the major identified flavonoid glycoside. Quantum-chemical calculations were made to find molecular properties using the DFT/B3LYP method with 6-311++G(2d,2p) basis set. Quantum-chemical values such as EHOMO, ELUMO, energy gap, ionization potential, chemical hardness, softness, and electronegativity values were calculated and discussed. Phenolic compounds detected by HPLC-DAD-UV in the GCAE were docked into the active site of 3 HCoV-229E targets (PDB IDs. 2ZU2, 6U7G, 7VN9, and 6WTT) to find the potential inhibitors that block the Coronavirus infection pathways from quantum and docking data for these compounds. There are good adaptations between the theoretical and experimental results showing that rutin has the highest activity against Low Pathogenic HCoV-229E in the GCAE extract.

Objectives: Tabernaemontana pandacaqui is used in Indonesian folklore as a cure for ulcers, inflammation, skin sores and stomach pain, it was recently grown in Egypt for ornamental purposes.It can host endophytes which produce variety of secondary metabolites of potential biological activities. Based on traditional use of this plant, it was essential to study endophytes living in this host plant and evaluate their phytochemical and biological values. Methods: T. pandacaqui leaves were used as the microbial host material for the isolated fungus which was mass cultured and extracted. Fungal ethyl acetate extract was analyzed with GC-MS. Quantitative and qualitative identification of the compounds was performed based on the comparison of their retention times and mass spectra with those of the NIST, WILLY library data of the GC-MS system. Its antioxidant activity was evaluated using DPPH and ABTS assays and expressed as Trolox Equivalent Antioxidant Capacity (TEAC) and the cytotoxic screening against four cell lines was carried out using SRB assay. Results: The isolated fungus (TMP16) was identified as Aspergillus species.GC-MS analysis revealed the presence of high percentage of nitrogenous compounds (75.38%) of which porphyrin derivatives dominate (42.85%). The fungal extract gave antioxidant scavenging power of 881.49 ± 44.6 and 866.86 ± 50.0 μM TE/ mg extract (TEAC) in both DPPH and ABTS assays respectively. While it showed no cytotoxic activity against A-549, HepG2, PC-3 and MCF-7 cell lines with the used concentrations. Conclusion: Ethyl acetate extract of (TMP16), isolated from T. pandacaqui leaves for the first time, exhibited a significant antioxidant activity which may be attributed to high percentage of porphyrin derivatives.