Cytotoxic alkaloids from the root of Zanthoxylum paracanthum (mildbr) Kokwaro

TfOH-Catalyzed Reactions of Aryl Methyl Ketones with Ynamides: Synthesis of 1-Amino-1H-indenes and 2,4-Dienamides

The efficient synthesis of 1-amino-1H-indenes and 2,4-dienamides was realized via TfOH-catalyzed reactions of aryl methyl ketones with terminal ynamides in two distinct pathways. Aromatic ketones with high electrophilicity underwent [3 + 2] annulation with ynamides to produce 1-amino-1H-indenes, while aromatic ketones with low electrophilicity proceeded under the same conditions to afford 2,4-dienamides. Furthermore, the obtained 1-amino-1H-indenes could be converted into the corresponding 1H-indenes and dihydro-1H-indenes in excellent yields.

Nitidine Chloride Triggers Autophagy and Apoptosis of Ovarian Cancer Cells through Akt/mTOR Signaling Pathway

OBJECTIVE

Ovarian cancer (OC) is the eighth most common cancer with high mortality in women worldwide. Currently, compounds derived from Chinese herbal medicine have provided a new angle for OC treatment.

METHODS

In this study, the cell proliferation and migration of ovarian cancer A2780/SKOV3 cells were inhibited after being treated with nitidine chloride (NC) by using MTT and Wound-Healing Assay. Flow cytometry analysis indicated NC-induced apoptosis of ovarian cancer cells, and AO and MDC staining showed that NC treatment induced the appearance of autophagosomes and autophagic lysosomes in ovarian cancer cells.

RESULTS

Through the autophagy inhibition experiment of chloroquine, it was proved that NC significantly further promoted apoptosis in ovarian cancer cells. Furthermore, NC proved that it could significantly decrease the expression of autophagy-related genes such as Akt, mTOR, P85 S6K, P70 S6K, and 4E-BP1.

CONCLUSION

Therefore, we suggest that NC could trigger autophagy and apoptosis of ovarian cancer cells through Akt/mTOR signaling pathway, and NC may potentially be a target for chemotherapy against ovarian cancer.

Alkaloids of Dicranostigma franchetianum (Papaveraceae) and Berberine Derivatives as a New Class of Antimycobacterial Agents

Tuberculosis (TB) is a widespread infectious disease caused by Mycobacterium tuberculosis. The increasing incidence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains has created a need for new antiTB agents with new chemical scaffolds to combat the disease. Thus, the key question is: how to search for new antiTB and where to look for them? One of the possibilities is to search among natural products (NPs). In order to search for new antiTB drugs, the detailed phytochemical study of the whole Dicranostigma franchetianum plant was performed isolating wide spectrum of isoquinoline alkaloids (IAs). The chemical structures of the isolated alkaloids were determined by a combination of MS, HRMS, 1D, and 2D NMR techniques, and by comparison with literature data. Alkaloids were screened against Mycobacterium tuberculosis H37Ra and four other mycobacterial strains (M. aurum, M. avium, M. kansasii, and M. smegmatis). Alkaloids 3 and 5 showed moderate antimycobacterial activity against all tested strains (MICs 15.625–31.25 µg/mL). Furthermore, ten semisynthetic berberine (16a–16k) derivatives were developed and tested for antimycobacterial activity. In general, the derivatization of berberine was connected with a significant increase in antimycobacterial activity against all tested strains (MICs 0.39–7.81 μg/mL). Two derivatives (16e, 16k) were identified as compounds with micromolar MICs against M. tuberculosis H37Ra (MIC 2.96 and 2.78 µM). All compounds were also evaluated for their in vitro hepatotoxicity on a hepatocellular carcinoma cell line (HepG2), exerting lower cytotoxicity profile than their MIC values, thereby potentially reaching an effective concentration without revealing toxic side effects.

A new C-C linked benzophenathridine-2-quinoline dimer, and the antiplasmodial activity of alkaloids from Zanthoxylum holstzianum

The CH₂Cl₂/MeOH (1:1) extract of Zanthoxylum holstzianum stem bark showed good antiplasmodial activity (IC₅₀ 2.5 ± 0.3 and 2.6 ± 0.3 µg/mL against the W2 and D6 strains of Plasmodium falciparum, respectively). From the extract five benzophenanthridine alkaloids [8-acetonyldihydrochelerythrine (1), nitidine (2), dihydrochelerythine (3), norchelerythrine (5), arnottianamide (8)]; a 2-quinolone alkaloid [N-methylflindersine (4)]; a lignan [4,4'-dihydroxy-3,3'-dimethoxylignan-9,9'-diyl diacetate (7)] and a dimer of a benzophenanthridine and 2-quinoline [holstzianoquinoline (6)] were isolated. The CH₂Cl₂/MeOH (1:1) extract of the root bark afforded 1, 3-6, 8, chelerythridimerine (9) and 9-demethyloxychelerythrine (10). Holstzianoquinoline (6) is new, and is the second dimer linked by a C-C bond of a benzophenanthridine and a 2-quinoline reported thus far. The compounds were identified based on spectroscopic evidence. Amongst five compounds (1-5) tested against two strains of P. falciparum, nitidine (IC₅₀ 0.11 ± 0.01 µg/mL against W2 and D6 strains) and norchelerythrine (IC₅₀ value of 0.15 ± 0.01 µg/mL against D6 strain) were the most active.