β-Sitosterol as a Promising Anticancer Agent for Chemoprevention and Chemotherapy: Mechanisms of Action and Future Prospects

Cancer is one of the primary causes of death worldwide, and its incidence continues to increase yearly. Despite significant advances in research, the search for effective and nontoxic preventive and therapeutic agents remains greatly important. Cancer is a multimodal disease, where various mechanisms play significant roles in its occurrence and progression. This highlights the need for multitargeted approaches that are not only safe and inexpensive but also provide effective alternatives for current therapeutic regimens. β-Sitosterol (SIT), the most abundant phytosterol found in various plant foods, represents such an option. Preclinical evidence over the past few decades has overwhelmingly shown that SIT exhibits multiple anticancer activities against varied cancers, such as liver, cervical, colon, stomach, breast, lung, pancreatic, and prostate cancers, in addition to leukemia, multiple myeloma, melanoma, and fibrosarcoma. In this article, we present the latest advances and perspectives on SIT-systematically summarizing its antitumor mechanisms of action into 7 main sections and combining current challenges and prospects-for its use as a promising agent for cancer prevention and treatment. In particular, SIT plays a role in cancer prevention and treatment mainly by enhancing apoptosis, inducing cell cycle arrest, bidirectionally regulating oxidative stress, improving metabolic reprogramming, inhibiting invasion and metastasis, modulating immunity and inflammation, and combating drug resistance. Although SIT holds such great promise, the poor aqueous solubility and bioavailability coupled with low targeting efficacy limit its therapeutic efficacy and clinical application. Further research on novel drug delivery systems may improve these deficiencies. Overall, through complex and pleiotropic mechanisms, SIT has good potential for tumor chemoprevention and chemotherapy. However, no clinical trials have yet proven this potential. This review provides theoretical basis and rationality for the further design and conduct of clinical trials to confirm the anticancer activity of SIT.

Suppression on allergic airway inflammation of dehulled adlay (Coix lachryma-jobi L. var. ma-yuen Stapf) in mice and anti-degranulation phytosterols from adlay bran

Adlay (Coix lachryma-jobi L. var. ma-yuen Stapf) seeds have been used in Asia for thousands years to treat warts, chapped skin, rheumatism, and neuralgia. The anti-allergic activity of dehulled adlay (DA) seeds was identified, and the bran (AB) is regarded as the main functional constituent in the edible part. However, no study has focused on in vivo acute anti-allergic airway inflammation. In the present report, we investigated DA methanolic extract (DAM) reversed ovalbumin (OVA)/methacholine (Mch)-induced airway hypersensitivity, decreased interleukin (IL)-4, IL-5, and IL-13 levels from splenocytes, suppressed tumor necrosis factor (TNF)-α, IL-1β, and IL-13 levels and reduced eosinophil counts and eotaxin in bronchoalveolar lavage fluid (BALF), which imply that the modulatory effects of DA should involve allergic degranulation. Further, seven phytosterols were isolated from AB ethanolic extract (ABE); among them, 3-O-caffeoyl-5β-sitostan-3-ol, β-sitosterol 3-O-glucopyranoside and β-sitosterol inhibited β-hexosaminidase release from A23187-stimulated RBL-2H3 cells with percentages of 54.1%, 52.0% and 48.5%, respectively, at 50 μM. In addition, β-sitosterol reduced immunoglobulin (Ig)E-stimulated degranulation on RBL-2H3 cells in a dose-dependent manner. The phytosterols were the predominant components based on gas chromatography (GC) analysis. This is the first study to demonstrate that DA suppressed OVA/Mch-induced acute airway inflammation. The phytosterols in AB showed significant anti-degranulation activities, and may be regarded as the indicative components of AB for anti-allergy effects.

Pueraria tuberosa: A Review on Traditional Uses, Pharmacology, and Phytochemistry

Pueraria tuberosa (Roxb. ex Willd.) DC. (Fabaceae), also known as Indian Kudzu (vidari kand), is a perennial herb distributed throughout India and other Asian countries. Traditionally, tuber and leaves of this plant have extensively been reported for nutritional and medicinal properties in Ayurveda as well as in Chinese traditional practices. The objective of the present review is to compile and update the published data on traditional uses, pharmacological potential, and phytochemistry of compounds isolated from the plant Pueraria tuberosa. P. tuberosa extracts and its purified compounds possess multiple activities such as anticancer, anticonvulsant, antidiabetic, antifertility, anti-inflammatory, antioxidant, anti-stress, antiulcerogenic, cardioprotective, hypolipidemic, hepatoprotective, immunomodulatory, nephroprotective, nootropic, neuroprotective, and wound healing. Tuber and leaf extracts of P. tuberosa contain several bioactive constituents such as puerarin, daidzein, genistein, quercetin, irisolidone, biochanin A, biochanin B, isoorientin, and mangiferin, which possess an extensive range of pharmacological activities. The extensive range of pharmacological properties of P. tuberosa provides opportunities for further investigation and presents a new approach for the treatment of ailments. Many phytochemicals have been identified and characterized from P. tuberosa; however, some of them are still unexplored, and there is no supporting data for their activities and exact mechanisms of action. Therefore, further investigations are warranted to unravel the mechanisms of action of individual constituents of this plant.

Gallnuts: A Potential Treasure in Anticancer Drug Discovery

Introduction. In the discovery of more potent and selective anticancer drugs, the research continually expands and explores new bioactive metabolites coming from different natural sources. Gallnuts are a group of very special natural products formed through parasitic interaction between plants and insects. Though it has been traditionally used as a source of drugs for the treatment of cancerous diseases in traditional and folk medicinal systems through centuries, the anticancer properties of gallnuts are barely systematically reviewed. Objective. To evidence the traditional uses and phytochemicals and pharmacological mechanisms in anticancer aspects of gallnuts, a literature review was performed. Materials and Methods. The systematic review approach consisted of searching web-based scientific databases including PubMed, Web of Science, and Science Direct. The keywords for searching include gallnut, Galla Chinensis, Rhus chinensis, Rhus potaninii, Rhus punjabensis, nutgall, gall oak, Quercus infectoria, Quercus lusitanica, and galla turcica. Two reviewers extracted papers independently to remove the papers unrelated to the anticancer properties of gallnuts. Patents, abstracts, case reports, and abstracts in symposium and congress were excluded. Results and Conclusion. As a result, 14 articles were eligible to be evaluated. It is primarily evident that gallnuts contain a number of bioactive metabolites, which account for anticancer activities. The phytochemical and pharmacological studies reviewed strongly underpin a fundamental understanding of anticancer properties for gallnuts (Galla Chinensis and Galla Turcica) and support their ongoing clinical uses in China. The further bioactive compounds screening and evaluation, pharmacological investigation, and clinical trials are expected to progress gallnut-based development to finally transform the wild medicinal gallnuts to the valuable authorized anticancer drugs.

Inhibitory effect of naringenin via IL-13 level regulation on thymic stromal lymphopoietin-induced inflammatory reactions

Naringenin (NG) has various beneficial properties, such as anti-cancer and anti-inflammatory effects. Thymic stromal lymphopoietin (TSLP) induces mast cell proliferation and inflammatory reactions. The aim of this study was to investigate the regulatory effect of NG on TSLP-induced mast cell proliferation and inflammatory reactions using human mast cell line (HMC-1) cells. HMC-1 cells were pre-treated with NG and then treated with TSLP. HMC-1 cells proliferation was determined by quantifying bromodeoxyuridine incorporation. Levels of anti-apoptotic and pro-apoptotic factors were analyzed by western blot analysis. The productions and mRNA expressions of interleukin (IL)-13 and tumour necrosis factor-α (TNF-α) were analyzed by ELISA and quantitative real-time PCR. We found that NG significantly attenuated HMC-1 cells proliferation and Ki-67 mRNA expression promoted by TSLP. NG significantly suppressed mRNA expression of TSLP receptor and IL-7 receptor α in TSLP-treated HMC-1 cells. NG significantly down-regulated levels of phosphorylated-signal transducer and activation of transcription 6 and murine double-minute 2 in TSLP-treated HMC-1 cells, up-regulated levels of cleaved poly ADP-ribose polymerase and p53 in TSLP-treated HMC-1 cells. Furthermore, NG significantly decreased the productions and mRNA expressions of IL-13 and TNF-α in TSLP-treated HMC-1 cells. These results suggest NG has an inhibitory effect on mast cell-mediated allergic inflammatory reactions.

A dichloromethane fraction of Triticum aestivum sprouts reduces allergic immune response through inhibiting Th2 differentiation in ovalbumin‑immunized mice

Triticum aestivum sprouts are small shoots that germinate from seeds and are consumed as a dietary supplement. The present study aimed to determine whether a dichloromethane fraction isolated from Triticum aestivum sprouts (TDF) suppressed the allergic immune response in ovalbumin (OVA)‑sensitized mice. In vivo experiments were performed by administering TDF or vehicle to mice during the sensitization and this was immediately followed by an intradermal injection of OVA into the ears. Splenocytes isolated from OVA‑sensitized mice were pre‑treated with TDF and re‑challenged with OVA for ex vivo evaluation. Results demonstrated that TDF suppressed the inflammatory response in ear tissues and levels of total immunoglobulin (Ig)E and OVA‑specific IgE in serum. TDF inhibited the production of interleukin (IL)‑4 and expression of GATA‑binding protein‑3 (GATA‑3) transcription factor which regulates the differentiation of naïve T helper (Th) cells into Th2 cells in OVA‑stimulated splenocytes. TDF inhibited Th1‑associated cytokine interferon‑γ and IL‑12 production and downregulated the expression of Th1 specific transcription factor T‑box 21 in OVA‑stimulated splenocytes. Overall, these results indicated that TDF attenuates OVA‑induced allergic immune response by suppressing the production of Th2 specific cytokine IL‑4, through inhibiting transcription factor GATA‑3, and suggests that TDF may exhibit the potential to regulate the immune response in allergic diseases.