Synthesis and biological assessment of new benzothiazolopyridine and benzothiazolyl- triazole derivatives as antioxidant and antibacterial agents

ABSTRACT. A novel series of benzothiazolopyridine derivatives was synthesized via interaction of -2-(benzothiazol-2-yl)-3-(4-chlorophenyl)acrylonitrile (2) with a diverse of commercially available reagents (indandione, thiobarbituric acid, and malononitrile). Moreover, a novel group of benzothiazole linked substituted 1,2,3-triazole derivatives were synthesized by exploring the chemical behavior of 5-benzothiazolyl-2-(4-chlorophenyl)-triazol-4-amine through refluxing in glacial acetic acid, condensation with phthalic anhydride, and cyanoacetylation reactions. All newly synthetized compounds have been tested for their antioxidant and antibacterial activities compared with ascorbic acid and Ampicillin as reference drugs, respectively. The benzothiazolo- pyridopyrimidine compound 6 was found the most potent antioxidant agent with IC50 = 0.015 mg/mL compared to the results of ascorbic acid (IC50 = 0.022 mg/mL). The investigated compounds showed no antibacterial properties against Gram-negative bacterial species, Pseudomonas aeruginosa and Escherichia coli. Benzothiazolopyridine derivative 5 displayed the best growth inhibition against Gram-positive bacteria, Staphylococcus aureus and Bacillus cereus with inhibition zones 24 and 20 mm, respectively.   KEY WORDS: Benzothiazole, Pyridobenzothiazole, 1,2,3-Triazole, Naphtharidine, Antioxidant   Bull. Chem. Soc. Ethiop. 2022, 36(2), 451-463.                                                              DOI: https://dx.doi.org/10.4314/bcse.v36i2.17                                                     &nbsp

Vincamine and 14-epi-vincamine indole alkaloids from Ambelania occidentalis

AbstractTwo indole alkaloids, Vincamine 1 and 14-epi-vincamine 2 were isolated here for the first time from Ambelania occidentalis. The structures of these compounds were elucidated by one and two dimension NMR and MS spectroscopy

Antioxidant, cytotoxic, antitumor, and protective DNA damage metabolites from the red sea brown alga Sargassum sp

Background: Macroalgae can be viewed as a potential antioxidant and anti-inflammatory sources owing to their capability of producing compounds for its protection from environmental factors such as heat, pollution, stress, oxygen concentration, and UV radiations. Objective: To isolate major compounds which are mainly responsible for the pharmacological activity of brown alga under investigation, Sargassum sp. Materials and Methods: Algal material was air dried, extracted with a mixture of organic solvents, and fractionated with different adsorbents. The structures of obtained pure compounds were elucidated with different spectroscopic techniques, and two pure materials were tested for protection of DNA from damage, antioxidant, antitumor, and cytotoxicity. Results: Four pure compounds were obtained, of which fucosterol (1) and fucoxanthin (4) were tested; it was found that fucoxanthin has strong antioxidant and cytotoxicity against breast cancer (MCF-7) with IC 50 = 11.5 ΅g/ml. Conclusion: The naturally highly conjugated safe compound fucoxanthin could be used as antioxidant and as an antitumor compound

New cytotoxic isoprenoid derivatives from the Red Sea soft coral<i> Sarcophyton glaucum</i>

<div><p>Chemical investigation of the soft coral <i>Sarcophyton glaucum</i> collected from the Red Sea led to isolation of 11 isoprenoidal metabolites (<b>1</b>–<b>11</b>). A new sesquiterpenoid, 6-oxo-germacra-4(15),8,11-triene (<b>1</b>), a new natural cembranoid, sarcophinediol, along with two known sesquiterpenoids (<b>2</b> and <b>3</b>) and seven known cembranoids (<b>5</b>–<b>11</b>) was obtained. The structures of the compounds were established based on their NMR, MS, IR and UV spectral data. All compounds were evaluated for their cytotoxicity employing three cancer cell lines (HepG2, MCF-7 and HCT116). Compounds <b>4</b> and <b>6</b> showed significant cytotoxicity towards HepG2 with IC₅₀ values of 18.8 ± 0.07 and 19.9 ± 0.02 μM; respectively. Compounds <b>5</b>–<b>7</b> exhibited potent cytotoxicity against MCF-7 cells with IC₅₀ values of 9.9 ± 0.03, 2.4 ± 0.04 and 3.2 ± 0.02 μM, respectively. Compounds <b>1</b>, <b>4</b> and <b>5</b> showed significant activities towards HCT116 cells with IC₅₀ values of 29.4 ± 0.03, 19.4 ± 0.02 and 25.8 ± 0.03 μM, respectively.</p></div

Cytotoxic scalarane-type sesterterpenes from the Saudi Red Sea sponge <i>Hyrtios erectus</i>

<p>The CHCl₃/MeOH extract of the marine sponge <i>Hyrtios erectus</i> showed cytotoxicity against three cancer cell lines HepG2, A549, and PC-3 with IC₅₀ 0.055, 0.044, and 0.023 μg/ml, respectively. The CH₂Cl₂ soluble fraction afforded three scalarane sesterterpenes (<b>1–3</b>) along with a cholestane derivative (<b>4</b>) and an indole alkaloid (<b>5</b>). Chemical structures were established by spectroscopic techniques and comparison with data reported in the literature. Scalarinol (<b>1</b>) was found as a new metabolite, while heteronemin (<b>2</b>) and 12-<i>O</i>-deacetyl-19-deoxyscalarin (<b>3</b>) are known compounds. <b>1–3</b> exhibited cytotoxic activity against the cancer cell lines with IC₅₀ values ranging from 14 to 230 μM. The molecular affinity to the DNA was employed as marker to examine the proposed mechanism of cytotoxic activities. Compound <b>2</b>, with IC₅₀ 28 μg/ml, displayed the highest affinity to the DNA.</p