Chemical Components of the Fruits of Morus nigra Linn.: Methyl Caffeate as a Potential Anticancer Agent by Targeting 3-Phosphoglycerate Dehydrogenase

Identification of benzo[b]thiophene-1,1-dioxide derivatives as novel PHGDH covalent inhibitors

The increased de novo serine biosynthesis confers many advantages for tumorigenesis and metastasis. Phosphoglycerate dehydrogenase (PHGDH), a rate-limiting enzyme in serine biogenesis, exhibits hyperactivity across multiple tumors and emerges as a promising target for cancer treatment. Through screening our in-house compound library, we identified compound Stattic as a potent PHGDH inhibitor (IC50 = 1.98 ± 0.66 µM). Subsequent exploration in structural activity relationships led to the discovery of compound B12 that demonstrated the increased enzymatic inhibitory activity (IC50 = 0.29 ± 0.02 μM). Furthermore, B12 exhibited robust inhibitory effects on the proliferation of MDA-MB-468, NCI-H1975, HT1080 and PC9 cells that overexpress PHGDH. Additionally, using a [U-13C6]-glucose tracing assay, B12 was found to reduce the production of glucose-derived serine in MDA-MB-468 cells. Finally, mass spectrometry-based peptide profiling, mutagenesis experiment and molecular docking study collectively suggested that B12 formed a covalent bond with Cys421 of PHGDH.

Screening of anti-melanoma compounds from Morus alba L.: Sanggenon C promotes melanoma cell apoptosis by disrupting intracellular Ca2+ homeostasis

ETHNOPHARMACOLOGICAL RELEVANCE

Morus alba L. is a widespread plant that has long been considered to have remarkable medical values, including anti-inflammation in Traditional Chinese Medicine (TCM). The components of Morus Alba L. constituents have been extensively studied and have been shown to have high prospects for cancer therapy. However, limited investigations have been done on the bioactive compounds in Morus alba L.

AIM OF THE STUDY

This study aimed to systematically examine the anticancer properties of 28 commercially available compounds from Morus alba L. against melanoma cells in vitro. Additionally, the anticancer mechanisms of the bioactive compound exhibiting the most significant potential were further studied.

MATERIALS AND METHODS

The anti-proliferative effects of Morus alba L.-derived compounds on melanoma cells were determined by colony formation assays. Their effects on cell viability and apoptosis were determined using the CCK8 assay and flow cytometry, respectively. The binding affinity of identified Morus alba L. compounds with anticancer activities towards melanoma targets was analyzed via molecular docking. The molecular mechanism of Sanggenon C was explored using soft agar assays, EdU incorporation assays, flow cytometry, western blotting, transcriptome analysis, and xenograft assays.

RESULTS

Based on colony formation assays, 11 compounds at 20 μM significantly inhibited colony growth on a panel of melanoma cells. These compounds displayed IC50 values (half maximal inhibitory concentrations) ranging from 5 μM to 30 μM. Importantly, six compounds were identified as novel anti-melanoma agents, including Sanggenon C, 3'-Geranyl-3-prenyl-2',4',5,7-tetrahydroxyflavone, Moracin P, Moracin O, Kuwanon A, and Kuwanon E. Among them, Sanggenon C showed the most potent effects, with an IC50 of about 5 μM, significantly reducing proliferation and inducing apoptosis in melanoma cells. Based on the xenograft model assay, Sanggenon C significantly inhibited melanoma cell proliferation in vivo. Sanggenon C triggered ER stress in a dose-dependent manner, which further disrupted cellular calcium ion (Ca2+) homeostasis. The Ca2+ chelator BAPTA partially restored cell apoptosis induced by Sanggenon C, confirming that Ca2+ signaling contributed to the anticancer activity of Sanggenon C against melanoma.

CONCLUSIONS

In our study, 11 compounds demonstrated anti-melanoma properties. Notably, Sanggenon C was found to promote apoptosis by disrupting the intracellular calcium homeostasis in melanoma cells. This study provides valuable information for the future development of novel cancer therapeutic agents from Morus alba L.

Progress of isolation, chemical synthesis and biological activities of natural chalcones bearing 2-hydroxy-3-methyl-3-butenyl group

Chalcones have a three-carbon α,β-unsaturated carbonyl system composed of two phenolic rings. Many chalcones have shown broad spectrum of biological activities with clinical potentials against various diseases. They are usually abundant in seeds, fruit skin, bark and flowers of most edible plants. Among them, chalcones bearing 2-hydroxy-3-methyl-3-butenyl (HMB) group have been reported several times in the past few decades due to their novel scaffolds and numerous interesting biological activities. In this paper, we reviewed the isolation of twelve natural chalcones and a natural chalcone-type compound bearing 2-hydroxy-3-methyl-3-butenyl group discovered so far, and reviewed their synthesis methods and biological activities reported in the literature. We anticipate that this review will inspire further research of natural chalcones.

Phytochemical Composition of Different Botanical Parts of Morus Species, Health Benefits and Application in Food Industry

In recent years, mulberry has acquired a special importance due to its phytochemical composition and its beneficial effects on human health, including antioxidant, anticancer, antidiabetic and immunomodulatory effects. Botanical parts of Morus sp. (fruits, leaves, twigs, roots) are considered a rich source of secondary metabolites. The aim of our study was to highlight the phytochemical profile of each of the botanical parts of Morus tree, their health benefits and applications in food industry with an updated review of literature. Black and white mulberries are characterized in terms of predominant phenolic compounds in correlation with their medical applications. In addition to anthocyanins (mainly cyanidin-3-O-glucoside), black mulberry fruits also contain flavonols and phenolic acids. The leaves are a rich source of flavonols, including quercetin and kaempferol in the glycosylated forms and chlorogenic acid as predominant phenolic acids. Mulberry bark roots and twigs are a source of prenylated flavonoids, predominantly morusin. In this context, the exploitation of mulberry in food industry is reviewed in this paper, in terms of developing novel, functional food with multiple health-promoting effects.