Recent advances in cancer chemoprevention with phytochemicals

Karakteristik Fisiko-Kimia Ekstrak Etanolik Kulit Bawang Merah (Allium ascalonicum L.) yang Diekstrak Menggunakan Microwave-Assisted Extraction

Kulit bawang merah (Allium ascalonicum L.) mengandung senyawa fitokimia yang bisa berfungsi sebagai antioksidan. Tujuan penelitian ini adalah mempelajari pengaruh konsentrasi etanol dan lama ekstraksi terhadap karakteristik fisik-kimia ekstrak kulit bawang merah menggunakan microwave-assisted extraction. Penelitian ini menggunakan Rancangan Acak Kelompok (RAK) dengan dua faktor yaitu faktor konsentrasi etanol (70, 80, dan 90%) dan lama waktu ekstraksi (10, 20 dan 30 menit). Setiap kombinasi perlakuan diulang tiga kali. Hasil penelitian menunjukkan konsentrasi etanol memberikan pengaruh yang nyata (α=0,05) terhadap total fenol, total flavonoid, aktivitas antioksidan, sifat kemerahan (a*) dan kekuningan (b*). Kondisi ekstraksi yang optimum untuk kulit bawang merah adalah 70% etanol dan lama ekstraksi 20 menit. Ekstrak yang dihasilkan mempunyai karakteristik sebagai berikut: total fenol 31,34±2,28 mg GAE/g; total flavonoid 26,12±0,75 mg QE/g; dan aktivitas antioksidan sebesar 65,94±0,55 %, nilai kecerahan (L*) 26,2 ± 0,12; nilai kemerahan (a*) -1,0 ± 0,44; nilai kekuningan (b*) 3,6 ± 0,17. Kesimpulannya, konsentrasi etanol dan lama ekstraksi mempengaruhi sifat fisik-kimia ekstrak kulit bawang merah.AbstractShallot skin (Allium ascalonicum L.) contains phytochemicals that can be a source of natural antioxidants. This research was done to study ethanol concentration and extraction time on the physicochemical characteristic of shallot skin extract using microwave-assisted extraction. This research used Randomized Block Design with two factors that were ethanol concentration (70, 80 and 90%) and extraction time (10, 20 and 30 min.). Each combination of the treatment was repeated in three times. The results showed that ethanol concentration and extraction time gave significant effect (α=0.05) on total phenol, total flavonoids, antioxidant activity, redness (a*), and yellowish (b*). The optimum extraction condition for shallot skin was 70% ethanol and 20 min of extraction. The extract had characteristics as follows: total phenol 31.34±2.28 mg GAE/g; total flavonoid 26.12±0.75 mg QE/g; antioxidant activity 65.94±0.55 %, brightness value (L*) of 26.2 ± 0.12; redness value (a*) of -1.0 ± 0.44; yellowish value (b*) of 3.6 ± 0.17. As conclusion, ethanol concentration and extraction time affected physicochemical characteristic of shallot skin extract. 

Ellagitannins from jabuticaba (Myrciaria jaboticaba) seeds attenuated inflammation, oxidative stress, aberrant crypt foci, and modulated gut microbiota in rats with 1,2 dimethyl hydrazine-induced colon carcinogenesis

Since dietary factors are thought to be responsible for high colon cancer risk, we investigated the chemopreventive effect of jabuticaba seed extract (LJE) by administering yogurt with or without LJE against 1,2 dimethyl hydrazine (DMH)-induced colon carcinogenesis in rats. Results showed that LJE contained a total phenolic content of 57.16 g/100 g of seed extract in which 7.67 and 10.09 g/100 g represented total flavonoids and ellagitannins, respectively. LJE protected DNA and human LDL against induced in vitro oxidation, which was associated with the ellagitannin content and with the free-radical scavenging and reducing capacities. LJE alone had a non-clastogenicity/aneugenicity property, but in combination with cisplatin, it enhanced the chromosome aberrations in cancer cells. In colon cancer-induced rats, yogurt with or without LJE caused a reduction in pro-inflammatory parameters, decreased the RNA expression of antiapoptotic cytokines and increased the expression of proapoptotic cytokines. Moreover, LJE attenuated colon cancer initiation and progression by decreasing aberrant crypt foci and LJE recovered the gut microbiome. Together, this evidence suggests that LJE provides chemopreventive protection against colon cancer development by reducing inflammation and increasing proapoptotic pathways.

Natural isoflavonoids in invasive cancer therapy: From bench to bedside

Cancer is a public health problem worldwide, and one of the crucial steps within tumor progression is the invasion and metastasis of cancer cells, which are directly related to cancer-associated deaths in patients. Recognizing the molecular markers involved in invasion and metastasis is essential to find targeted therapies in cancer. Interestingly, about 50% of the discovered drugs used in chemotherapy have been obtained from natural sources such as plants, including isoflavonoids. Until now, most drugs are used in chemotherapy targeting proliferation and apoptosis-related molecules. Here, we review recent studies about the effect of isoflavonoids on molecular targets and signaling pathways related to invasion and metastasis in cancer cell cultures, in vivo assays, and clinical trials. This review also reports that glycitein, daidzein, and genistein are the isoflavonoids most studied in preclinical and clinical trials and displayed the most anticancer activity targeting invasion-related proteins such as MMP-2 and MMP-9 and also EMT-associated proteins. Therefore, the diversity of isoflavonoids is promising molecules to be used as chemotherapeutic in invasive cancer. In the future, more clinical trials are needed to validate the effectiveness of the various natural isoflavonoids in the treatment of invasive cancer.

Natural products in the reprogramming of cancer epigenetics

Owing to the technological advancements, including next generation sequencing, the significance of deregulated epigenetic mechanisms in cancer initiation, progression and treatment has become evident. The accumulating knowledge relating to the epigenetic markers viz. DNA methylation, Histone modifications and non-coding RNAs make them one of the most interesting candidates for developing anti-cancer therapies. The reversibility of deregulated epigenetic mechanisms through environmental and dietary factors opens numerous avenues in the field of chemoprevention and drug development. Recent studies have proven that plant-derived natural products encompass a great potential in targeting epigenetic signatures in cancer and numerous natural products are being explored for their possibility to be considered as "epi-drug". This review intends to highlight the major aberrant epigenetic mechanisms and summarizes the essential functions of natural products like Resveratrol, Quercetin, Genistein, EGCG, Curcumin, Sulforaphane, Apigenin, Parthenolide and Berberine in modulating these aberrations. This knowledge along with the challenges and limitations in this field has potential and wider implications in developing novel and successful therapeutic strategies. The increased focus in the area will possibly provide a better understanding for the development of dietary supplements and/or drugs either alone or in combination. The interaction of epigenetics with different hallmarks of cancer and how natural products can be utilized to target them will also be interesting in the future therapeutic approaches.

Plant-Derived Anticancer Compounds as New Perspectives in Drug Discovery and Alternative Therapy

Despite the recent advances in the field of chemically synthetized pharmaceutical agents, nature remains the main supplier of bioactive molecules. The research of natural products is a valuable approach for the discovery and development of novel biologically active compounds possessing unique structures and mechanisms of action. Although their use belongs to the traditional treatment regimes, plant-derived compounds still cover a large portion of the current-day pharmaceutical agents. Their medical importance is well recognized in the field of oncology, especially as an alternative to the limitations of conventional chemotherapy (severe side effects and inefficacy due to the occurrence of multi-drug resistance). This review offers a comprehensive perspective of the first blockbuster chemotherapeutic agents of natural origin’s (e.g. taxol, vincristine, doxorubicin) mechanism of action using 3D representation. In addition is portrayed the step-by-step evolution from preclinical to clinical evaluation of the most recently studied natural compounds with potent antitumor activity (e.g. resveratrol, curcumin, betulinic acid, etc.) in terms of anticancer mechanisms of action and the possible indications as chemotherapeutic or chemopreventive agents and sensitizers. Finally, this review describes several efficient platforms for the encapsulation and targeted delivery of natural compounds in cancer treatment

Pivotal Role of the Interaction Between Herbal Medicines and Gut Microbiota on Disease Treatment

With the recognition of the important role of gut microbiota in both health and disease progression, attempts to modulate its composition, as well as its co-metabolism with the organism, have attracted special attention. Abundant studies have demonstrated that dysfunction or imbalance of gut microbiota is closely related to disease progression, including endocrine diseases, neurodegenerative diseases, tumors, cardiovascular diseases, etc. Herbal medicines have been applied to prevent and treat diseases worldwide for hundreds of years. Although the underlying mechanism seems to be complex, one of the important ones is through modulating gut microbiota. In this review, co-metabolism between herbal medicines and microbiota, as well as the potential pathways are summarized from most recent published papers.

The Anticancer Potential of Apigenin Via Immunoregulation

Apigenin is an edible flavonoid widely distributed in natural plants, including most vegetables and fruits. Previous studies have revealed that apigenin possesses multiple biological functions by demonstrating antiinflammatory, anti-oxidative, anti-bacterial, anti-viral, anti-tumor and cardiovascular protective effects. Furthermore, recent progressions have disclosed a novel perspective of the anti-cancer roles of apigenin through its immunoregulatory functions. With the rapid progression of the groundbreaking strategies being developed for cancer immunotherapy, its immunoregulatory roles are being recognized as intriguing features of the multifaceted apigenin. However, the current understanding of this emerging role of apigenin still remains limited. Therefore, in the present review, recent advances on the immunoregulatory properties of apigenin in various diseases with a special focus on neoplasm, are summarized. Clinical strategies of cancer immunotherapy are briefly introduced and findings on apigenin linked to immunoregulatory roles in immunotherapy-associated aspects are brought together. The bioactivity, bioavailability, toxicity and potential of apigenin, to be considered as a therapeutic agent in anti-tumor immunotherapy, is discussed. Disclosed molecular mechanisms underlying the immunoregulatory roles of apigenin in cancer immunotherapy are also summarized. Based on findings from the literature, apigenin has the potential to serve as a prospective adjuvant for anti-cancer immunotherapy and warrants further investigations.

Anticancer activity of Vicenin-2 against 7,12 dimethylbenz[a]anthracene-induced buccal pouch carcinoma in hamsters

Buccal mucosa carcinoma is a significant cause of death in developing nations. Vicenin-2 is a significant bioactive compound found in Ocimum sanctum Linn or Tulsi that possesses several pharmacologic properties. Our focus is to understand the possible impact of Vicenin-2 on 7,12-dimethylbenz[a]anthracene (DMBA)-induced oral carcinogenesis in hamsters. Buccal carcinoma was induced by treatment with carcinogenic DMBA, three times a week for 14 weeks. We determined 100% tumor incidence, abnormal tumor volume, inclined tumor burden, and deduced body weight in DMBA-induced oral squamous cell carcinoma (OSCC) hamsters. The upregulation of cytokine levels (interleukin [IL]-6, IL-1β, and tumor necrosis factor-alpha [TNF-α]) was observed in DMBA-induced OSCC hamsters. Moreover, dysplastic, hyperplastic, and squamous cell carcinoma was identified in the DMBA-induced OSCC hamsters. The diminished activities of lipid peroxidation and enzymatic/nonenzymatic antioxidants were observed in DMBA-induced hamsters. Furthermore, the high expression of proliferating cell nuclear antigen (PCNA), Cyclin-D1, and Bcl-2, and attenuated Bax expression were observed in DMBA-induced hamsters. Our study results explored that Vicenin-2 (30 mg/kg) treated with DMBA-brushed hamsters averted tumor incidence, improved the antioxidant status, and inhibited lipid peroxidation. Moreover, Vicenin-2 inhibited the immunohistochemical expression of PCNA, Cyclin-D1, and Bcl-2, and significantly restored apoptotic Bax levels. The Vicenin-2 treatment prevents the lesion formation in the oral epithelium of the DMBA-induced hamsters. The Vicenin-2 treatment potentially halts the proinflammatory cytokines (IL-6, IL-1β, and TNF-α) production in OSCC hamsters. Thus, we proved that Vicenin-2 prevents DMBA-induced buccal carcinogenesis in hamsters via improving antioxidants by modulating apoptotic and cytokines signaling pathways.

The Role of Autophagy in Gastric Cancer Chemoresistance: Friend or Foe?

Gastric cancer is the third most common cause of cancer-related death worldwide. Drug resistance is the main inevitable and vital factor leading to a low 5-year survival rate for patients with gastric cancer. Autophagy, as a highly conserved homeostatic pathway, is mainly regulated by different proteins and non-coding RNAs (ncRNAs) and plays dual roles in drug resistance of gastric cancer. Thus, targeting key regulatory nodes in the process of autophagy by small molecule inhibitors or activators has become one of the most promising strategies for the treatment of gastric cancer in recent years. In this review, we provide a systematic summary focusing on the relationship between autophagy and chemotherapy resistance in gastric cancer. We comprehensively discuss the roles and molecular mechanisms of multiple proteins and the emerging ncRNAs including miRNAs and lncRNAs in the regulation of autophagy pathways and gastric cancer chemoresistance. We also summarize the regulatory effects of autophagy inhibitor and activators on gastric cancer chemoresistance. Understanding the vital roles of autophagy in gastric cancer chemoresistance will provide novel opportunities to develop promising therapeutic strategies for gastric cancer.

Dihydroartemisinin Inhibits the Proliferation of Esophageal Squamous Cell Carcinoma Partially by Targeting AKT1 and p70S6K

Dihydroartemisinin (DHA), a sesquiterpene lactone with endoperoxide bridge, is one of the derivatives of artemisinin. In addition to having good antimalarial properties, DHA exhibits anticancer effects including against malignant solid tumors. However, the mechanism by which DHA inhibits the progression of esophageal cancer, especially esophageal squamous cell carcinoma (ESCC), is unclear. In this study, DHA was found to inhibit the proliferation of ESCC, and the underlying molecular mechanisms were explored. DHA inhibited ESCC cells proliferation and anchorage-independent growth. Flow cytometry analysis revealed that DHA significantly blocked cell cycle in the G1 phase. The results of human phospho-kinase array revealed that DHA downregulated the levels of p70S6K^T389 and p70S6K^T421/S424. Furthermore, the levels of mTOR^S2448, p70S6K^T389, p70S6K^T421/S424 and RPS6^S235/S236 were decreased after DHA treatment in KYSE30 and KYSE150 cells. We then explored the proteins targeted by DHA to inhibit the mTOR-p70S6K-RPS6 pathway. Results of the in vitro kinase assay revealed that DHA significantly inhibited phosphorylation of mTOR^S2448 by binding to AKT1 and p70S6K kinases. In vivo, DHA inhibited the tumor growth of ESCC patient-derived xenografts and weakened p-mTOR, p-p70S6K, and p-RPS6 expression in tumor tissues. Altogether, our results indicate that DHA has antiproliferative effects in ESCC cells and can downregulate mTOR cascade pathway partially by binding to AKT1 and p70S6K. Thus, DHA has considerable potential for the prevention or treatment of ESCC.

Food chemoprevention and air pollution: the health comes with eating

Ambient air pollution is known to be an important causative agent of many non-communicable diseases, mainly due to fine particulate matter (PM_2.5). According to Global Burden Disease study in 2015, the estimated premature deaths caused by PM_2.5 were 4.2 million. Besides deaths, airborne pollution's effect on human health also has dramatic economic and social costs, contributing greatly to disability-adjusted life-year (DALY). To reduce the health impact is necessary a double approach, which includes the improvement of air quality and food chemoprevention, aimed at enhancing the homeostatic abilities of exposed subjects. The scavenging, antioxidant, and anti-inflammatory properties of nutraceuticals effectively counteract the pathogenic mechanisms common in almost all non-communicable diseases associated with air pollutants. Moreover, several bioactive compounds of food modulate, by epigenetic mechanisms, the metabolism of xenobiotics, favouring conjugation reactions and promoting excretion. This narrative review summarize the numerous pieces of evidence collected in the last decades by observational and experimental studies which underline the chemopreventive role of flavonoids, contained in several fruits and consumer beverages (wine, tea, etc.), and isothiocyanate sulforaphane, contained in the cruciferous vegetables belonging to the genus Brassica. These bioactive compounds, enhancing the individual homeostatic abilities, reduce the harmful effects of airborne pollution.

Chemopreventive and Anticancer Effects of Thymoquinone: Cellular and Molecular Targets

Thymoquinone (TQ) is a bioactive component derived from the seeds of Nigella sativa that are commonly as black cumin. Evidences indicate that the medicinal properties of TQ have been recognized for more than 2000 years. TQ has been shown to possess potent chemopreventive properties that include anti-inflammatory and anti-neoplastic activities. Recent studies have unraveled the multiple mechanisms through which TQ exerts its chemopreventive and anticancer activity in different cancer cells in a contextual manner. The present review aims to provide a brief compendium on the molecular mechanisms through which TQ inhibits signaling pathways underlying cancer genesis, progression, and metastasis.

Assessing the Current State of Lung Cancer Chemoprevention: A Comprehensive Overview

Chemoprevention of lung cancer is thought to significantly reduce the risk of acquiring these conditions in the subpopulation of patients with underlying health issues, such as chronic obstructive pulmonary disorder and smoking-associated lung problems. Many strategies have been tested in the previous decades, with very few translating to successful clinical trials in specific subpopulations of patients. In this review, we analyze these strategies, as well as new approaches that have emerged throughout the last few years, including synthetic lethality concept and microbiome-induced regulation of lung carcinogenesis. Overall, the continuous effort in the area of lung chemoprevention is required to develop practical therapeutical approaches. Given the inconsistency of results obtained in clinical trials targeting lung cancer chemoprevention in various subgroups of patients that differ in the underlying health condition, race, and gender, we believe that individualized approaches will have more promise than generalized treatments.

Garcinol Exhibits Anti-Neoplastic Effects by Targeting Diverse Oncogenic Factors in Tumor Cells

Garcinol, a polyisoprenylated benzophenone, is the medicinal component obtained from fruits and leaves of Garcinia indica (G. indica) and has traditionally been extensively used for its antioxidant and anti-inflammatory properties. In addition, it has been also been experimentally illustrated to elicit anti-cancer properties. Several in vitro and in vivo studies have illustrated the potential therapeutic efficiency of garcinol in management of different malignancies. It mainly acts as an inhibitor of cellular processes via regulation of transcription factors NF-κB and JAK/STAT3 in tumor cells and have been demonstrated to effectively inhibit growth of malignant cell population. Numerous studies have highlighted the anti-neoplastic potential of garcinol in different oncological transformations including colon cancer, breast cancer, prostate cancer, head and neck cancer, hepatocellular carcinoma, etc. However, use of garcinol is still in its pre-clinical stage and this is mainly attributed to the limitations of conclusive evaluation of pharmacological parameters. This necessitates evaluation of garcinol pharmacokinetics to precisely identify an appropriate dose and route of administration, tolerability, and potency under physiological conditions along with characterization of a therapeutic index. Hence, the research is presently ongoing in the dimension of exploring the precise metabolic mechanism of garcinol. Despite various lacunae, garcinol has presented with promising anti-cancer effects. Hence, this review is motivated by the constantly emerging and promising positive anti-cancerous effects of garcinol. This review is the first effort to summarize the mechanism of action of garcinol in modulation of anti-cancer effect via regulation of different cellular processes.