Gossypin: A flavonoid with diverse pharmacological effects

Gossypin induces apoptosis and autophagy via the MAPK/JNK pathway in HT‑29 human colorectal cancer cells

Gossypin, a flavone found in Hibiscus vitifolius, exhibits antioxidant, antidiabetic, anti‑inflammatory and anticancer effects. The present study investigated the potential of gossypin to induce apoptosis and autophagy in HT‑29 human colorectal cancer (CRC) cells, and assessed its association with the MAPK/JNK pathway. Cell viability assays, DAPI staining, flow cytometry, acridine orange staining, western blotting, hematoxylin and eosin staining, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and immunohistochemistry were performed. The results revealed an increased number of apoptotic bodies, higher apoptosis rates and enhanced autophagy in gossypin‑treated HT‑29 cells. To investigate autophagy during cell death, the effects of the early autophagy inhibitor 3‑methyladenine (3‑MA) and the late autophagy inhibitor hydroxychloroquine on cell viability and the expression of apoptosis‑related proteins were assessed. Significant increases in cell viability were observed following 3‑methyladenine pretreatment, as well as a decrease in the expression levels of Bcl‑2 and an increase in Bax. The analysis of MAPK pathway proteins following treatment with gossypin revealed that the levels of phosphorylated (p‑)JNK and p‑p38 were significantly increased in a concentration‑dependent manner. The JNK inhibitor SP600125 was used to confirm the role of the JNK pathway in gossypin‑induced apoptosis and autophagy. Moreover, gossypin reduced the volume of HT‑29 tumors in mice, and western blotting indicated the induction of apoptosis and autophagy in these tumors in vivo. Finally, TUNEL and immunohistochemistry experiments confirmed the induction of apoptosis and p‑JNK upregulation in these tumors in vivo. In conclusion, the present study suggested that gossypin may induce MAPK/JNK‑mediated apoptosis and autophagy in HT‑29 CRC cells, highlighting the potential of gossypin as an anticancer agent.

The potential of blackcurrant, fig, and grape leaf extracts in the development of new preparations for overcoming antibiotic resistance and enhancing the efficacy of chemotherapeutic agents

The presented study aimed to assess the efficacy of crude leaf hydroethanolic extracts from blackcurrant, fig, and grape leaves in reversing antibiotic resistance and enhancing chemotherapeutic efficacy. The viability tests were employed to assess the resistance-modifying properties of the extracts both in antibiotic-resistant bacterial cells and cancer cell-lines. To elucidate the potential mechanisms of the antibiotic modulatory activity of test extracts, the changes in H+-fluxes across the cell membrane and their impact on the H+-translocating F0F1-ATPase activity in antibiotic-resistant Escherichia coli explored. Qualitative metabolomic characterization of the extracts was performed using LC-Q-Orbitrap HRMS, and quantitative analysis was carried out with UHPLC-PDA. Experiments on doxorubicin-resistant and susceptible HT-29 cells revealed that all three extracts reversed antibiotic resistance in HT-29R cells, making them susceptible to doxorubicin in a dose-dependent manner. Notably, blackcurrant, and fig significantly reduced the minimum inhibitory concentrations of ampicillin and kanamycin against resistant E. coli strains. Our results indicated that all plant extracts enhanced H+-fluxes in the investigated bacterial strain and promoted ATPase activity, suggesting a potential role in altering bacterial membrane integrity. LC-Q-Orbitrap HRMS analysis identified more than 100 major peaks, with flavonoids and phenolics being the dominant constituents. The study underscores the potential of the selected plant extracts in developing of new agents to overcome antibiotic resistance and enhance the efficacy of chemotherapeutic agents. Importantly, although these plant leaves are often considered as bio-waste, they can be used as valuable sources of bioactive compounds. This underlines the importance of re-evaluating agricultural by-products for their potential in pharmacological applications, fostering a sustainable approach in drug development.

Gossypin-Loaded Ethosome Gel for Cutaneous Administration: A Preliminary Study on Melanoma Cells

A preformulative study was conducted to produce and characterize ethosomes for the transdermal delivery of gossypin. This plant-derived compound possesses many pharmacological properties, including antitumoral potential. Ethosome dispersions were designed as transdermal delivery systems for gossypin, employing two different production procedures. The evaluation of vesicle size distribution by photon correlation spectroscopy, morphology by cryogenic transmission electron microscopy, and gossypin entrapment capacity, as well as in vitro release and permeation by vertical diffusion cells, enabled us to select a production strategy based on the injection of a phosphatidylcholine ethanolic solution in water. Indeed, vesicles prepared by this method were almost unilamellar and measured roughly 150 nm mean diameter while displaying an entrapment capacity higher than 94%. Moreover, vesicles prepared by the ethanol injection method enabled us to control gossypin release and to improve its permeation with respect to the solution of the drug. To obtain semi-solid forms suitable for cutaneous gossypin administration, ethosome dispersions were thickened with 0.5% w/w xanthan gum, selected by a spreadability test. These ethosome gels were then further characterized by small- and wide-angle X-ray scattering, while their antioxidant activity was demonstrated in vitro by a radical scavenging assay. Finally, in vitro biological studies were conducted on A375 melanoma cell lines. Namely, wound healing and cell migration assays confirmed the potential antitumoral effect of gossypin, especially when loaded in the selected ethosomal gel. The promising results suggest further investigation of the potential of gossypin-loaded ethosomal gel in the treatment of melanoma.

Targeting RSK2 in Cancer Therapy: A Review of Natural Products

P90 ribosomal S6 kinase 2 (RSK2) is an important member of the RSK family, functioning as a kinase enzyme that targets serine and threonine residues and contributes to regulating cell growth. RSK2 comprises two major functional domains: the N-terminal kinase domain (NTKD) and the C-terminal kinase domain (CTKD). RSK2 is situated at the lower end of the Mitogen-activated protein kinases (MAPK) signaling pathway and is phosphorylated by the direct regulation of Extracellular signal-regulating kinase (ERK). RSK2 has been found to play a pivotal role in regulating cell proliferation, apoptosis, metastasis, and invasion in various cancer cells, including breast cancer and melanoma. Consequently, RSK2 has emerged as a potential target for the development of anti-cancer drugs. Presently, several inhibitors are undergoing clinical trials, such as SL0101. Current inhibitors of RSK2 mainly bind to its NTK or CTK domains and inhibit their activity. Natural products serve as an important resource for drug development and screening and with the potential to identify RSK2 inhibitors. This article discusses how RSK2 influences tumor cell proliferation, prevents apoptosis, arrests the cell cycle process, and promotes cancer metastasis through its regulation of downstream pathways or interaction with other biological molecules. Additionally, the paper also covers recent research progress on RSK2 inhibitors and the mechanisms of action of natural RSK2 inhibitors on tumors. This review emphasizes the significance of RSK2 as a potential therapeutic target in cancer and offers a theoretical basis for the clinical application of RSK2 inhibitors.

Study on the crystallinity of PEG on the crystalline size of flavonoids in a crystalline dispersion system

Poor water solubility and low bioavailability of flavonoids present significant barriers to their development and application. To address these challenges, this study explores the use of crystalline solid dispersions (CSDs) to reduce drug crystalline size and enhance in vivo bioavailability. The CSDs were prepared using a spray-drying technique with chrysin (CHY) and quercetin (QUR) as model drugs and various molecular weights of polyethylene glycol (PEG) as carriers. The authors systematically investigated the factors influencing the interaction between flavonoids and PEG in CSDs. These factors included the relationships between intermolecular interactions and PEG molecular weight, crystallinity, microstructures such as crystalline domain size and crystal morphology of the flavonoids and PEG in CSDs, crystalline size of the drug in CSDs, and in vitro dissolution rate and in vivo pharmacokinetics. Our results indicated that the interaction between flavonoids and PEG in CSDs was influenced more by PEG crystallinity than by its molecular weight. Lower crystallinity of PEG, achieved through recrystallization, led to stronger intermolecular interactions with the drugs. Specifically, PEG8000 exhibited the lowest crystallinity, indicating a higher content of PEG in the amorphous state, which interacted more effectively with the amorphous drug in CSDs. This interaction significantly inhibited drug crystallization growth, resulting in a marked decrease in drug crystalline domain size and crystalline size. Consequently, PEG8000 was identified as the optimal carrier for preparing CSDs, achieving the best cumulative dissolution percentage. The QUR/PEG8000-CSD formulation increased the cumulative dissolution percentage and oral bioavailability of QUR by 18.76 and 20.66 times, respectively, compared to QUR alone. This study demonstrates that PEG crystallinity, following recrystallization, directly affects its intermolecular interactions with the drug, thereby impacting drug crystalline size and dissolution rate.

Mechanisms of Sepsis-Induced Acute Lung Injury and Advancements of Natural Small Molecules in Its Treatment

Sepsis-induced acute lung injury (ALI), characterized by widespread lung dysfunction, is associated with significant morbidity and mortality due to the lack of effective pharmacological treatments available clinically. Small-molecule compounds derived from natural products represent an innovative source and have demonstrated therapeutic potential against sepsis-induced ALI. These natural small molecules may provide a promising alternative treatment option for sepsis-induced ALI. This review aims to summarize the pathogenesis of sepsis and potential therapeutic targets. It assembles critical updates (from 2014 to 2024) on natural small molecules with therapeutic potential against sepsis-induced ALI, detailing their sources, structures, effects, and mechanisms of action.

Native-compound-Coupled Affinity Matrix (NCAM) in target identification and validation of bioactive compounds: Application, mechanism and outlooks

In drug discovery and development, the direct target identification of bioactive small molecules plays a significant role for understanding the mechanism of action, predicting the side effects, and rationally designing more potent compounds. However, due to the complicated regulatory processes in a cell together with thousands of biomacromolecules, target identification is always the major obstacle. New methods and technologies are continuously invented to tackle this problem. Nevertheless, the mainly used tools possess several disadvantages. High synthetic skills are typically required to laboriously synthesize a probe for protein enrichment. To detect the ligand-protein interaction by analyzing proteins' responses to proteolytic or thermal treatment, costly and precise instruments are always necessary. Therefore, convenient and practical techniques are urgently needed. Over the past decades, a strategy using native compounds without the requirement of chemical modification, also termed Native-compound-Coupled Affinity Matrix (NCAM), is developing continuously. Two practical tactics based on "label-free" compounds have been invented and used, that is Photo-cross-linked Small-molecule Affinity Matrix (PSAM) and Native-compound-Coupled CNBr-activated Beads (NCCB). Presently, we will elucidate the characteristics, coupling mechanism, advantages and disadvantages, and future prospect of NCAM in specific target identification and validation.

Influence of Intermolecular Interactions on Crystallite Size in Crystalline Solid Dispersions

Crystalline solid dispersions (CSDs) represent a thermodynamically stable system capable of effectively reducing the crystallite size of drugs, thereby enhancing their solubility and bioavailability. This study uses flavonoid drugs with the same core structures but varying numbers of hydroxyl groups as model drugs and poloxamer 188 as a carrier to explore the intrinsic relationships between drug-polymer interactions, crystallite size, and in vitro dissolution behavior in CSDs. Initially, we investigate the interactions between flavonoid drugs and P188 by calculating Hansen solubility parameters, determination of Flory-Huggins interaction parameters, and other methods. Subsequently, we explore the crystallization kinetics of flavonoid drugs and P188 in CSD systems using polarized optical microscopy and powder X-ray diffraction. We monitor the domain size and crystallite size of flavonoids in CSDs through powder X-ray diffraction and a laser-particle-size analyzer. Finally, we validate the relationship between crystallite size and in vitro dissolution behavior through powder dissolution. The results demonstrate that, as the number of hydroxyl groups increases, the interactions between drugs and polymers become stronger, making drug crystallization in the CSD system less likely. Consequently, reductions in crystalline domain size and crystallite size become more pronounced, leading to a more significant enhancement in drug dissolution.

Advances in Molecular Regulation of Prostate Cancer Cells by Top Natural Products of Malaysia

Prostate cancer (PCa) remains both a global health burden and a scientific challenge. We present a review of the molecular targets driving current drug discovery to fight this disease. Moreover, the preventable nature of most PCa cases represents an opportunity for phytochemicals as chemopreventive when adequately integrated into nutritional interventions. With a renovated interest in natural remedies as a commodity and their essential role in cancer drug discovery, Malaysia is looking towards capitalizing on its mega biodiversity, which includes the oldest rainforest in the world and an estimated 1200 medicinal plants. We here explore whether the list of top Malay plants prioritized by the Malaysian government may fulfill the potential of becoming newer, sustainable sources of prostate cancer chemotherapy. These include Andrographis paniculate, Centella asiatica, Clinacanthus nutans, Eurycoma longifolia, Ficus deltoidea, Hibiscus sabdariffa, Marantodes pumilum (syn. Labisia pumila), Morinda citrifolia, Orthosiphon aristatus, and Phyllanthus niruri. Our review highlights the importance of resistance factors such as Smac/DIABLO in cancer progression, the role of the CXCL12/CXCR4 axis in cancer metastasis, and the regulation of PCa cells by some promising terpenes (andrographolide, Asiatic acid, rosmarinic acid), flavonoids (isovitexin, gossypin, sinensetin), and alkylresorcinols (labisiaquinones) among others.