Identification of Chrysoplenetin from Vitex negundo as a Potential Cytotoxic Agent against PANC-1 and a Panel of 39 Human Cancer Cell Lines (JFCR-39)

Comprehensive Review on Herbal Medicine: Emphasis on Current Therapy and Role of Phytoconstituents for Cancer Treatment

INTRODUCTION

Cancer poses a significant public health challenge in both developed and developing nations, with a rising global incidence of patients facing the threat of death due to abnormal cell proliferation.

AIM

Review explores the utilization of different parts of herbal medicinal plants and their active pharmaceutical constituents in the prevention and treatment of various types of cancer.

METHODOLOGY

Various anticancer medicinal plants have been identified, demonstrating their therapeutic effects by inhibiting cancer-stimulating enzymes and hormones, activating DNA repair processes, boosting the synthesis of protective stimulants, reducing the formation of free radicals, and enhancing individual immunity. Data for this study were gathered from diverse online bibliographic and databases, including Google, Google Scholar, Mendeley, Springer Link, Research Gate, and PubMed.

RESULT

Herbal drugs have a huge contribution to the inhibition of the progression of cancer.A large volume of clinical studies has reported the beneficial effects of herbal medicines on the survival, immune modulation, and quality of life (QOL) of cancer patients, when these herbal medicines are used in combination with conventional therapeutics.

CONCLUSION

The latest medicines for the clinical purpose (Above 50 %) are derived from herbal products. Furthermore, combination of these herbs with nanotechnology shows promise in treating specific carcinomas.

Dihydrochalcones as antitumor agents

Dihydrochalcones are a class of secondary metabolites, possessing several biological properties such as antitumor, antioxidant, antibacterial, antidiabetic, estrogenic, anti-inflammatory, antithrombotic, antiviral, neuroprotective and immunomodulator properties; therefore, they are currently considered promising candidates in the drug discovery process. This review intend to debate their pharmacological actions with a particular attention to their antitumor activity against a panel of cancer cell-lines and to the description of the inhibition mechanisms of cell proliferation such as the regulation of angiogenesis, apoptosis, etc etc.

Traditional uses, phytochemistry, and pharmacology of genus Vitex (Lamiaceae)

Vitex, the genus of the family Lamiaceae, comprises of about 230 species mostly distributed in the warm regions of Europe and temperate regions of Asia. Several Vitex species have been used as folk medicine in different countries for the treatment of various kinds of diseases and ailments. The main aim of this review is to collect and analyze the scientific information available about the Vitex species regarding their chemical constituents and pharmacological activities. The phytochemical investigation of various Vitex species has resulted in the isolation of about 556 chemical constituents belong to various chemical category viz. iridoids, diterpenoids, triterpenoids, flavonoids, lignans, sesquiterpenoids, monoterpenoids, ecdysteroids, and others. The crude extracts of different Vitex species as well as pure phytochemicals exhibited a wide spectrum of in-vitro and in-vivo pharmacological activities. In the present review, the scientific literature data on the ethnopharmacological, phytochemical, and pharmacological investigations on the genus Vitex are summarized. More attention should be given in future research to evaluate the pharmacological potential with detailed mechanism of actions for the pure compounds, extracts of plants from this genus. Moreover, their clinical study is needed to justify their use in modern medicine and to further exploring this genus for new drug discovery.

A pharmacognostic approach for mitigating pancreatic cancer: emphasis on herbal extracts and phytoconstituents

Background

Pancreatic cancer is studied as one of the most lethal cancers with currently no control of its lethality, mainly due to its late diagnosis and lack of foolproof treatment processes. Despite continuous efforts being made in looking for therapies to deal with cancer, it keeps on being a labyrinth for the researchers. Efforts like discovering new treatment options, repurposing existing drugs, are continuously made to deal with this cancer.

Main body

With the urge to get answers and the fact that nature has all roots of therapeutics, efforts are made in the direction of finding those answers for providing ministrations for pancreatic cancer from plant products. Plant products are used as treatment options either directly in the form of extracts or an alternative to them is individual phytochemicals that are either isolated from the plants or are commercially synthesized for various purposes. In this review, we put forward such pharmacognostic initiatives made in combating pancreatic cancer, focusing mainly on plant extracts and various phytochemicals; along with the mechanisms which they triggered to fulfill the need for cytotoxicity to pancreatic cancer cells (in vitro and in vivo).

Conclusion

This study will thus provide insights into new combination therapy that can be used and also give a clue on which plant product and phytoconstituent can be used in dealing with pancreatic cancer.

Graphical abstract

Discovery of a "Cocktail" of Potential SARS-COV-2 Main Protease Inhibitors through Virtual Screening of Known Chemical Components of Vitex negundo L. ("Lagundi")

AIM

The prevailing crisis caused by the COVID-19 pandemic demands the development of effective therapeutic agents that can be implemented with minimal to zero adverse effects.

BACKGROUND

Vitex negundo L. (VNL) is a medicinal plant with reported efficacy against respiratory diseases and some of the COVID-19 symptoms. Funded by the Department of Science and Technology (DOST), the University of the Philippines - Philippine General Hospital (UP-PGH) is currently conducting clinical trials of VNL and other medicinal plants as adjuvant therapeutic agents against mild cases of COVID-19. The basis for the clinical trials is primarily the pharmacological efficacy of the medicinal plants against respiratory disorders and associated COVID-19 symptoms.

OBJECTIVE

This study assessed the in silico potential of VNL components against SARS-CoV-2 main protease (Mpro), an enzyme that plays an important role in COVID-19, the disease caused by the SARS-CoV-2.

METHOD

Phytochemical mining of VNL components from the literature was conducted. A database consisting of 250 known compounds from different parts of VNL was created and screened against SARS-CoV-2 Mpro using the PyRx virtual screening tool. The most promising components were further subjected to in silico absorption, distribution, metabolism, excretion, and toxicity (ADMET) analyses using the SwissADME web server and Toxtree software.

RESULTS

Virtual screening revealed that 102 VNL components in the database had comparable to or better binding affinities toward SARS-COV-2 Mpro than known chemical inhibitors (e.g. N3 and carmofur). It was determined that the active site of SARS-CoV-2 Mpro receptor consists of multiple H-donor and acceptor sites; hence, the most stable receptor-ligand complexes are generally formed by VNL ligands that establish effective H-bonding with the SARS-CoV-2 Mpro. The promising components, representing a "cocktail" of potential inhibitors also revealed interesting ADMET properties.

CONCLUSION

This in silico study identified VNL as a potential single source of a cocktail of SARS-CoV-2 Mpro inhibitors and a promising adjuvant therapeutic agent against COVID-19 or its symptoms. Furthermore, the study offers a rationale on phytochemical mining from medicinal plants as a means that can be implemented in the early stage of a drug discovery and development program.

Anti-Austerity Activity of Thai Medicinal Plants: Chemical Constituents and Anti-Pancreatic Cancer Activities of Kaempferia parviflora

Human pancreatic tumor cells have an intrinsic ability to tolerate nutrition starvation and survive in the hypovascular tumor microenvironment, the phenomenon termed as "austerity". Searching for an agent that inhibits such tolerance to nutrient starvation and kills the pancreatic cancer cells preferentially in nutrient-starvation is a unique anti-austerity strategy in anti-cancer drug discovery. In this strategy, plant extracts and compounds are tested against PANC-1 human pancreatic cancer cell line under the conditions of nutrient-deprived medium (NDM) and nutrient-rich medium (DMEM), to discover the compounds that show selective cytotoxicity in NDM. Screening of twenty-five Thai indigenous medicinal plant extracts for their anti-austerity activity against the PANC-1 human pancreatic cancer cell line in nutrient deprived medium (NDM) resulted in the identification of four active plants, Derris scandens, Boesenbergia pandurata, Citrus hystrix, and Kaempferia parviflora, with PC₅₀ values 0.5-8.9 µg/mL. K. parviflora extract also inhibited PANC-1 cancer cell colony formation. Phytochemical investigation of K. parviflora extract led to the isolation of fourteen compounds, including two polyoxygenated cyclohexanes (1 and 2), eleven flavonoids (3-13), and β-sitosterol (14). Stereochemical assignment of compound 1 was confirmed through X-ray analysis. All isolated compounds were tested for their preferential cytotoxicity against PANC-1 cells. Among them, 5-hydroxy-7-methoxyflavone (3) displayed the most potent activity with a PC₅₀ value of 0.8 µM. Mechanistically, it was found to induce apoptosis in PANC-1 cell death in NDM as evident by caspase cleavage. It was also found to inhibit PANC-1 cancer cell colony formation in DMEM. Therefore, compound 3 can be considered as a potential lead compound for the anticancer drug development based on the anti-austerity strategy.

Bioactive Compounds from Medicinal Plants in Myanmar

Myanmar is a country with rich natural resources and of these, medicinal plants play a vital role in the primary health care of its population. The people of Myanmar have used their own system of traditional medicine inclusive of the use of medicinal plants for 2000 years. However, systematic and scientific studies have only recently begun to be reported. Researchers from Japan, Germany, and Korea have collaborated with researchers in Myanmar on medicinal plants since 2000. During the past two decades, over 50 publications have been published in peer-reviewed journals. Altogether, 433 phytoconstituents, including 147 new and 286 known compounds from 26 plant species consisting of 29 samples native to Myanmar, have been collated. In this contribution, phytochemical and biological investigations of these plants, including information on traditional knowledge are compiled and discussed.

Potent Cytotoxic Natural Flavonoids: The Limits of Perspective

BACKGROUND

Besides the numerous biologic and pharmacologic functions in the human body that act as potent antioxidants, flavonoids (flavones, flavanones, flavonols, flavanols and isoflavones) are noted as cancer preventive or therapeutic agents.

METHODS

This review summarizes the published data using PubMed, Science Direct, and Scopus.

RESULTS

In this context, recognition and introduction of the most active cytotoxic flavonoids as promising agents for cancer therapy gives insight for further evaluations. However, there are some critical points that may affect the entering of flavonoids as active cytotoxic phytochemicals in the clinical phase. Issues such as the abundance of active species in nature, the methods of extraction and purification, solubility, pharmacokinetic profile, presence of the chiral moieties, method of synthesis, and structure modification may limit the entry of a selected compound for use in humans. Although plenty of basic evidence exists for cytotoxic/antitumor activity of the versatility of flavonoids for entry into clinical trials, the above-mentioned concerns must be considered.

CONCLUSION

This review is an effort to introduce cytotoxic natural flavonoids (IC50< 10 µM) that may have the potential to be used against various tumor cells. Also, active constituents, molecular mechanisms, and related clinical trials have been discussed as well as the limitations and challenges of using flavonoids in clinic.

Vitex negundo and its medicinal value

Natural products are rich in several potent bioactive compounds, targeting complex network of proteins involved in various diseases. Vitex negundo (VN), commonly known as "chaste tree", is an ethnobotanically important plant with enormous medicinal properties. Different species of Vitex vary in chemical composition, thus producing different phytochemicals. Several bioactive compounds have been extracted from leaves, seeds, roots in form of volatile oils, flavonoids, lignans, iridoids, terpenes, and steroids. These bioactive compounds exhibit anti-inflammatory, antioxidant, antidiabetic, anticancer, antimicrobial. VN is typically known for its role in the modulation of cellular events like apoptosis, cell cycle, motility of sperms, polycystic ovary disease, and menstrual cycle. VN, reportedly, perturbs many cancer-signaling pathways involving p-p38, p-ERK1/2, and p-JNK in LPS-elicited cells, N-terminal kinase (JNK), COX-1 pathways, MAPK, NF-κB, tumor necrosis factor α (TNF-α), Akt, mTOR, vascular endothelial growth factor, hypoxia-inducible factor (HIF-1α). Several bioactive compounds obtained from VN have been commercialized and others are under investigation. This is the first review presenting up-to-date information about the VN, its bioactive constituents and their mode of action.

Antiproliferative activity and phenotypic modification induced by selected Peruvian medicinal plants on human hepatocellular carcinoma Hep3B cells

ETHNOPHARMACOLOGICAL RELEVANCE

The high incidence of human hepatocellular carcinoma (HCC) in Peru and the wide use of medicinal plants in this country led us to study the activity against HCC cells in vitro of somes species used locally against liver and digestive disorders.

MATERIALS AND METHODS

Ethnopharmacological survey: Medicinal plant species with a strong convergence of use for liver and digestive diseases were collected fresh in the wild or on markets, in two places of Peru: Chiclayo (Lambayeque department, Chiclayo province) and Huaraz (Ancash department, Huaraz province). Altogether 51 species were collected and 61 ethanol extracts were prepared to be tested. Biological assessment: All extracts were first assessed against the HCC cell line Hep3B according a 3-step multi-parametric phenotypic assay. It included 1) the evaluation of phenotypic changes on cells by light microscopy, 2) the measurement of the antiproliferative activity and 3) the analysis of the cytoskeleton and mitosis by immunofluorescence. Best extracts were further assessed against other HCC cell lines HepG2, PLC/PRF/5 and SNU-182 and their toxicity measured in vitro on primary human hepatocytes.

RESULTS

Ethnopharmacological survey: Some of the species collected had a high reputation spreading over the surveyed locations for treating liver problems, i.e. Baccharis genistelloides, Bejaria aestuans, Centaurium pulchellum, Desmodium molliculum, Dipsacus fullonum, Equisetum bogotense, Gentianella spp., Krameria lapacea, Otholobium spp., Schkuhria pinnata, Taraxacum officinale. Hep3B evaluation: Fourteen extracts from 13 species (Achyrocline alata, Ambrosia arborescens, Baccharis latifolia, Hypericum laricifolium, Krameria lappacea, Niphidium crassifolium, Ophryosporus chilca, Orthrosanthus chimboracensis, Otholobium pubescens, Passiflora ligularis, Perezia coerulescens, Perezia multiflora and Schkuhria pinnata) showed a significant antiproliferative activity against Hep3B cells (IC50≤ 50µg/mL). This was associated with a lack of toxicity on primary human hepatocytes in vitro. Immunofluorescence experiments on Hep3B cells showed that crude extracts of Schkuhria pinnata and Orthrosanthus chimboracensis could block Hep3B cells in mitosis with an original phenotype. Crude extracts of Perezia coerulescens, Perezia multiflora, Achyrocline alata, Ophryosporus chilca, Otholobium pubescens and Hypericum laricifolium could modify the overall microtubule cytoskeletal dynamics of Hep3B cells in interphase by an original mechanism.

CONCLUSIONS

Our method allowed us to select 9 extracts which displayed antiproliferative activities associated with original cellular phenotypes on Hep3B cells, regarding known microtubule-targeting drugs. Both chemical and cellular studies are ongoing in order to elucidate natural compounds and cellular mechanisms responsible of the activities described.

Review on ethnomedicinal, phytochemical and pharmacological evidence of Himalayan anticancer plants

ETHNOPHARMACOLOGICAL RELEVANCE

Himalayan plants have 6500 years old history of being using as traditional medicines. Inhabitants of the region use indigenous knowledge for the preparation of various herbal recipes in order to treat different kinds of cancer. The aim of this review is to provide ethnopharmacological, phytochemical and toxicological overview of Himalayan medicinal plants having anticancer potential. This will provide a baseline for the discovery of new anticancer drugs.

MATERIAL AND METHODS

In total, 155 articles (mostly published) were reviewed by using online search engines like PubMed, Scopus, Google Scholar, Web of Science, and floras of different Himalayan countries.

RESULTS

Sixty four anticancer medicinal plants were documented belonging to 59 genera and 37 families. Majority of 42 plants were reported from India followed by 17 from Pakistan. Traditional healers in the region mostly prepare ethnomedicinal recipes from leaves (32% plants) and roots (30% plants) in the form of decoction. Thirty plants had reported anticancer related pharmacological and phytochemical activities. Of these, 27 plants were tested in-vitro on cellular models while 16 plants for in-vivo activities. Methanolic, ethanolic and ethylacetate extracts of plants have shown excellent cytotoxic activities against breast, stomach and blood cancers' cell lines. Total 14 active secondary metabolites including phenolic compounds, glycosides, terpenoids, lignans and alkynes from the studied plants were reported active against different cancer cell lines. Plants such as Bergenia ciliata, Argemone mexicana, Capsella bursa-pastoris and Centella asiatica had toxic effects on the living systems at higher doses when studied in-vivo.

CONCLUSIONS

Certain Himalayan medicinal plants present therapeutic properties against different types of cancer. However, not all of the plants have been fully analysed for in vitro, in vivo and toxicological activities, and isolation of secondary metabolites. Further ethnomedicinal studies would help in identifying potential medicinal plant species in the region to be analysed for detailed anticancer activities.

Effects of sesquiterpene, flavonoid and coumarin types of compounds from Artemisia annua L. on production of mediators of angiogenesis

BACKGROUND

In addition to recognized antimalarial effects, Artemisia annua L. (Qinghao) possesses anticancer properties. The underlying mechanisms of this activity are unknown. The aim of our experiments was to investigate the effects of distinct types of compounds isolated from A. annua on the immune-activated production of major mediators of angiogenesis playing a crucial role in growth of tumors and formation of metastasis.

METHODS

Included in the study were the sesquiterpene lactones artemisinin and its biogenetic precursors arteannuin B and artemisinic acid. The semi-synthetic analogue dihydroartemisinin was used for comparative purposes. The flavonoids were represented by casticin and chrysosplenol D, the coumarin type of compounds by 4-methylesculetin. Their effects on the lipopolysaccharide (LPS)-induced in vitro production of nitric oxide (NO) were analyzed in rat peritoneal cells using Griess reagent. The LPS-activated production of prostaglandin E2 (PGE2) and cytokines (VEGF, IL-1β, IL-6 and TNF-α) was determined in both rat peritoneal cells and human peripheral blood mononuclear cells using ELISA.

RESULTS

All sesquiterpenes (artemisinin, dihydroartemisinin, artemisinic acid, arteannuin B) significantly reduced production of PGE2. Arteannuin B also inhibited production of NO and secretion of cytokines. All NO, PGE2 and cytokines were suppressed by flavonoids casticin and chrysosplenol D. The coumarin derivative, 4-methylesculetin, was ineffective to change the production of any of these factors.

CONCLUSIONS

The inhibition of immune mediators of angiogenesis by sesquiterpene lactones and flavonoids may be one of the mechanisms of anticancer activity of Artemisia annua L.

Uvaridacols E-H, highly oxygenated antiausterity agents from Uvaria dac

Chemical investigation of the stems of Uvaria dac yielded four new highly oxygenated cyclohexene derivatives named uvaridacols E-H (1-4). Their structures were established through NMR and circular dichroism spectroscopic analysis. Uvaridacols E (1), F (2), and H (4) displayed weak preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrition-deprived conditions in a concentration-dependent manner, without causing toxicity in normal nutrient-rich conditions.

Antiausterity agents from Uvaria dac and their preferential cytotoxic activity against human pancreatic cancer cell lines in a nutrient-deprived condition

Human pancreatic cancer cell lines are known for their inherent tolerance to nutrition starvation, which enables them to survive under a hypovascular (austerity) tumor microenvironment. The search for agents that preferentially retard the survival of cancer cells under low nutrition conditions (antiausterity agent) is a novel approach to anticancer drug discovery. In this study, it was found that a dichloromethane extract of the stem of Uvaria dac preferentially inhibited PANC-1 human pancreatic cancer cells survival under nutrition-deprived conditions at a concentration of 10 μg/mL. Workup of this bioactive extract led to the discovery of (+)-grandifloracin (8) as a potent antiausterity agent as evaluated in a panel of four human pancreatic cancer cell lines, PANC-1 (PC(50), 14.5 μM), PSN-1 (PC(50), 32.6 μM), MIA PaCa-2 (PC(50), 17.5 μM), and KLM-1 (32.7 μM). (+)-Grandifloracin (8) has been isolated from a natural source for the first time. Its absolute stereochemistry was established by single-crystal X-ray crystallography and circular dichroism spectroscopic analysis. In addition to this, seven other new highly oxygenated cyclohexene derivatives, named uvaridacanes A (1) and B (2), uvaridacols A-D (3, 4, 6, 7), and uvaridapoxide A (5), were also isolated and structurally characterized.