Goniolanceolatins A-H, Cytotoxic Bis-styryllactones from Goniothalamus lanceolatus

Targeting epidermal growth factor receptor and its downstream signaling pathways by natural products: A mechanistic insight

The epidermal growth factor receptor (EGFR) is a transmembrane receptor tyrosine kinase (RTK) that maintains normal tissues and cell signaling pathways. EGFR is overactivated and overexpressed in many malignancies, including breast, lung, pancreatic, and kidney. Further, the EGFR gene mutations and protein overexpression activate downstream signaling pathways in cancerous cells, stimulating the growth, survival, resistance to apoptosis, and progression of tumors. Anti-EGFR therapy is the potential approach for treating malignancies and has demonstrated clinical success in treating specific cancers. The recent report suggests most of the clinically used EGFR tyrosine kinase inhibitors developed resistance to the cancer cells. This perspective provides a brief overview of EGFR and its implications in cancer. We have summarized natural products-derived anticancer compounds with the mechanistic basis of tumor inhibition via the EGFR pathway. We propose that developing natural lead molecules into new anticancer agents has a bright future after clinical investigation.

Discovery of plant-derived anti-tumor natural products: Potential leads for anti-tumor drug discovery

Natural products represent a paramount source of novel drugs. Numerous plant-derived natural products have demonstrated potent anti-tumor properties, thereby garnering considerable interest in their potential as anti-tumor drugs. This review compiles an overview of 242 recently discovered natural products, spanning the period from 2018 to the present. These natural products, which include 69 terpenoids, 42 alkaloids, 39 flavonoids, 21 steroids, 14 phenylpropanoids, 5 quinolines and 52 other compounds, are characterized by their respective chemical structures, anti-tumor activities, and mechanisms of action. By providing an essential reference and fresh insights, this review aims to support and inspire researchers engaged in the fields of natural products and anti-tumor drug discovery.

Isolation, structural elucidation, and cytotoxic activity investigation of novel styryl-lactone derivatives from Goniothalamus elegans: in vitro and in silico studies

Two styryl-lactone derivatives (1 and 2) were isolated from the aerial parts of Goniothalamus elegans. Compound 1 is a newly discovered natural product, and compound 2 is reported in this plant for the first time. The absolute configuration of 1 was determined based on the ECD spectrum. The two styryl-lactone derivatives were tested for cytotoxicity activity against five cancer cell lines and human embryonic kidney cells. The newly discovered compound demonstrated potent cytotoxicity, with IC50 values ranging from 2.05 to 3.96 μM. Computational methods were also applied to investigate the mechanism of the cytotoxic activity of the two compounds. Density functional theory and molecular mechanisms were used to assess the interaction between protein targets to compound 1 and 2, respectively, through the EGF/EGFR signaling pathway. The results indicated that 1 showed a strong binding affinity for two proteins EGFR and HER-2. Finally, ADMET predictions were used to validate the pharmacokinetics and toxicity of these compounds. The results showed that both compounds are likely to be absorbed in the gastrointestinal tract and penetrate the blood-brain barrier. Based on our findings, these compounds may have potential for further studies to be developed into active ingredients for cancer treatment.

Synthesis and crystal structure of (±)-Goniotamirenone C

The structure of the racemic version of the natural product Goniotamirenone C [racemic anti-6-(2-chloro-1-hy-droxy-2-phenyl-eth-yl)-2H-pyran-2-one, C13H11ClO3] at 150 K is reported. The compound crystallizes with monoclinic (P21/n) symmetry and with Z' = 2. One independent mol-ecule is ordered while the other independent mol-ecule exhibits an inter-esting whole-mol-ecule enanti-omeric disorder with occupancies of 0.846 (4) and 0.154 (4). The independent mol-ecules are hydrogen bonded with -OH⋯O=C linkages into chains that run parallel to the a axis. This structural analysis corrects our previous assignment as the syn isomer [Meesakul et al. (2020 ▸). Phytochemistry, 171, 112248-112255].

In vitro antiplasmodial and cytotoxicity activities of crude extracts and major compounds from Goniothalamus lanceolatus

ETHNOPHARMACOLOGICAL RELEVANCE

Malaria, a devastating infectious disease which was initially recognized as episodic fever, is caused by parasitic protozoan of the genus Plasmodium. Medicinal plants with ethnobotanical information to treat fever and/or malaria has been the key element in identifying potential plant candidates for antimalarial screening. Goniothalamus lanceolatus Miq. (Annonaceae) is used as a folk remedy, particularly to treat fever and skin diseases.

AIM OF THE STUDY

In this context, supported with previous preliminary data of its antiplasmodial activity, this study was undertaken to determine the in vitro antiplasmodial and cytotoxicity activities of G. lanceolatus crude extracts and its major compounds.

MATERIALS AND METHODS

The in vitro antiplasmodial activity was determined by parasite lactate dehydrogenase (pLDH) assay on chloroquine-sensitive (3D7) and chloroquine-resistant (K1) strains of Plasmodium falciparum. The cytotoxicity activity was evaluated using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay on hepatocellular carcinoma (HepG2) and normal liver (WRL-68) cell lines.

RESULTS

The root methanol extract possessed potent antiplasmodial activity against both P. falciparum 3D7 and K1 strains (IC₅₀ = 2.7 μg/ml, SI = 140; IC₅₀ = 1.7 μg/ml, SI = 236). Apart from the DCM extract of stem bark and root that were found to be inactive (IC₅₀ > 50 μg/ml) against 3D7 strain, all other tested crude extracts exhibited promising (5< IC₅₀ < 15 μg/ml) to moderate (15< IC₅₀ < 50 μg/ml) antiplasmodial activity against both strain. Additionally, only compound C (Parvistone D) exerted promising antiplasmodial activity against 3D7 strain (IC₅₀ = 7.5 μM, SI = 51) whereas compound A, B and D showed moderate antiplasmodial activity against the same strain (20 < IC₅₀ < 100 μM). Interestingly, when tested on K1 strain, compound A, C and D exhibited promising antiplasmodial activity (2 < IC₅₀ < 20 μM) while compound B exhibited moderate activity (IC₅₀ = 26.9 μM). Cytotoxicity study showed that all tested crude extracts and compounds were non-toxic on WRL-68 and HepG2 cell lines (CC₅₀ > 30 µg/ml, CC₅₀ > 10 µM, respectively), except for the hexane and DCM extracts of root, which exerted mild cytotoxicity on HepG2 cell line (IC₅₀ < 30 μg/ml).

CONCLUSIONS

This study suggests that the root methanol extract and compound C (Parvistone D) obtained from G. lanceolatus are highly potential for exploitation as source of antimalarial agents. Parvistone D is identified as one of the bioactive styryl lactones found in the plant extract. It is also noteworthy, that the extract and compound were more active against chloroquine-resistant (K1) strain of P. falciparum. Further studies are being carried out to assess their toxicity profile and antimalarial efficacy in animal model.