AIM OF THE REVIEW: The present review aims to collate and analyze the available data and information on distribution, traditional uses, chemical constituents and pharmacological activities of Blepharis.
METHODS: Scientific information of genus Blepharis was retrieved from the online bibliographic databases such as MEDLINE/PubMed, SciFinder, Web of Science and Google Scholar and secondary resources including books and proceedings.
RESULTS: Seven species of Blepharis were found to be reported frequently as useful in folklore in African and Asian countries. B. maderaspatensis was found to be widely used in Indian traditional medicines whereas the B. ciliaris and B. edulis were common in folklore of Egypt, Jordan, and Arabia. Active phytochemicals of Blepharis are flavonoids from B. ciliaris, alkaloids from B. sindica, phenolic acid derivatives, and phytosterols, and derivatives of hydroxamic acids from B. edulis resulted in possessing diverse biological properties such as anti-microbial, anti-inflammatory, and anti-cancer.
CONCLUSIONS: Various species of Blepharis were found to be used in traditional medicine systems in African and Asian countries. Few of these species were studied for their bioactive chemical constituents however the activity guided isolation studies are not performed. Similarly, detailed pharmacological studies in animal models to explore their mechanism of action are also not reported. Future studies should focus on these aspects related to the medicinally used species of Blepharis. The detailed and comprehensive comparative analysis presented here gives valuable information of the currently used Blepharis species and pave the way to investigate other useful species of Blepharis pertaining to ethnobotany, phytochemistry and discovery of new drugs.
OBJECTIVES: This review exhaustively gathers available information on ethnopharmacological uses, phytochemistry, and bioactivity studies on more than 20 species of Premna and critically analyzes the reports to provide the perspectives and directions for future research for the plants as potential source of drug leads and pharmaceutical agents.
METHODS: A literature search was performed on Premna species based on books of herbal medicine, major scientific databases including Chemical Abstract, Pubmed, SciFinder, Springerlink, Science Direct, Scopus, the Web of Science, Google Scholar, and ethnobotanical databases.
RESULTS: More than 250 compounds have been isolated and identified from Premna species, comprising of diterpenoids, iridoid glycosides, and flavonoids as the most common secondary metabolites, followed by sesquiterpenes, lignans, phenylethanoids, megastigmanes, glyceroglycolipids, and ceramides. Many in vitro and in vivo studies have been conducted to evaluate the biological and pharmacological properties of the extracts, and isolated compounds of Premna species with antimicrobial, antioxidant, anti-inflammatory, immunomodulatory, antihyperglycaemia, and cytotoxic activities.
CONCLUSION: The bioactive compounds responsible for the bioactivities of most plants have not been well identified as the reported in vivo pharmacological studies were mostly carried out on the crude extracts. The isolated bioactive components should also be further subjected to more preclinical studies and elaborate toxicity study before clinical trials can be pursued.
MATERIALS AND METHODS: All information on P. acidus was collected from various electronic database (ACS, PubMed, Scopus, Web of Science, SciFinder, Science Direct, Google Scholar, Springer, Wiley, Taylor and Mendeley) and also from those published materials (Ph.D. and M.Sc. dissertations and books) by using a combination of various meaningful keywords.
RESULTS: Phytochemical analyses on barks, leaves, roots and fruits of P. acidus identified triterpene, diterpene, sesquiterpene, and glycosides as predominant classes of bioactive substances found in this plant. P. acidus was reported with various pharmacological activities such as in vivo hepatoprotective and hypoglycemic, in vitro anti-oxidant, α-glucosidase inhibitory, anti-inflammatory and antimicrobial activities. However, none of these studies are with clinical research. Some of the studies were performed with only a single set of experiments or with a high dose of extract, and thus the validity of the experimental data may be questionable. In addition, most of the studies described were without identifying the effective components. Some of the assays were even without a positive control for comparison which makes results questionable.
CONCLUSION: Although P. acidus has been proven as a valuable medicinal source from its traditional uses. However, the pharmacological experiments conducted were not sufficient to verify its traditional uses. More investigation is required to confirm the traditional claims such as bioassay-guided isolation of bioactive compounds, detailed pharmacological investigations, clinical studies, and its toxicity investigation. Additionally, an experimental design with sufficient data replication, the use of controls and authenticated research materials, and the selection of a rationale dose or concentration for the analysis are keys to providing reproducible experimental data.
METHODS: A literature search was performed for the screening of natural and derived bio-active compounds which showed potent antiviral activity against coronaviruses using published articles, patents, clinical trials website (https://clinicaltrials.gov/) and web databases (PubMed, SCI Finder, Science Direct, and Google Scholar).
RESULTS: Through the screening for natural products with antiviral activities against different types of the human coronavirus, extracts of Lycoris radiata (L'Hér.), Gentiana scabra Bunge, Dioscorea batatas Decne., Cassia tora L., Taxillus chinensis (DC.), Cibotium barometz L. and Echinacea purpurea L. showed a promising effect against SARS-CoV. Out of the listed compound Lycorine, emetine dihydrochloride hydrate, pristimerin, harmine, conessine, berbamine, 4`-hydroxychalcone, papaverine, mycophenolic acid, mycophenolate mofetil, monensin sodium, cycloheximide, oligomycin and valinomycin show potent activity against human coronaviruses. Additionally, it is worth noting that some compounds have already moved into clinical trials for their activity against COVID-19 including fingolimod, methylprednisolone, chloroquine, tetrandrine and tocilizumab.
CONCLUSION: Natural compounds and their derivatives could be used for developing potent therapeutics with significant activity against SARS-COV-2, providing a promising frontline in the fighting against COVID-19.
AIM OF THIS REVIEW: The present study is a critical assessment of the state-of-the-art concerning the traditional uses, the phytochemistry and the pharmacology of species belonging to the genus Hedyosmum to suggest further research strategies and to facilitate the exploitation of the therapeutic potential of Hedyosmum species for the treatment of human disorders.
MATERIALS AND METHODS: The present review consists of a systematic overview of scientific literature concerning the genus Hedyosmum published between 1965 and 2018. Moreover, an older text, dated from 1843, concerning the traditional uses of H. bonplandianum Kunth has also been considered. Several databases (Francis & Taylor, Google Scholar, PubMed, SciELO, SciFinder, Springer, Wiley, and The Plant List Database) have been used to perform this work.
RESULTS: Sixteen species of the genus Hedyosmum have been mentioned as traditional remedies, and a large number of ethnomedicinal uses, including for the treatment of pain, depression, migraine, stomach-ache and ovary diseases, have been reported. Five species have been used as flavouring agents, tea substitutes or foods. Sesterterpenes, sesquiterpene lactones, monoterpenes, hydroxycinnamic acid derivatives, flavonoids, and neolignans have been reported as the most important compounds in these species. Studies concerning their biological activities have shown that members of the Hedyosmum genus possesses promising biological properties, such as analgesic, antinociceptive, antidepressant, anxiolytic, sedative, and hypnotic effects. Preliminary studies concerning the antibacterial, antioxidant, antiplasmodial, and antifungal activities of these plants as well as their cytotoxic activities against different tumour cell lines have been reported. Some active compounds from the Hedyosmum genus have been used as starting points for the innovative and bioinspired development of synthetic molecules. A critical assessment of these papers has been performed, and some conceptual and methodological problems have been identified regarding the materials and methods and the experimental design used in these studies, including a lack of ethnopharmacological research.
CONCLUSIONS: The present review partially confirms the basis for some of the traditional uses of Hedyosmum species (mainly H. brasiliense) through preclinical studies that demonstrated their antinociceptive and neuroprotective effects. Due to promising preliminary results, further studies should be conducted on 13-hydroxy-8,9-dehydroshizukanolide and podoandin. Moreover, several essential oils (EOs) from this genus have been preliminarily investigated, and the cytotoxic and antibacterial activities of H. brasiliense and H. sprucei EOs certainly deserve further investigation. From the promising findings of the present analysis, we can affirm that this genus deserves further research from ethnopharmacological and toxicological perspectives.
AIM OF THE REVIEW: This paper aimed to provide a critical review of current scenario on K. galanga. This review provides a current data on diversity, phytochemistry, pharmacological activities and traditional uses of K. galanga.
MATERIALS AND METHODS: The information and data on K. galanga were collated from various resources like ethnobotanical textbooks and literature databases such as PubMed, Science Direct, Wiley, Springer, Tailor and Francis, Scopus, Inflibnet, Google and Google Scholar.
RESULTS: The forty-nine phytochemicals including esters, terpenoids, flavonoids, thiourea derivatives, polysaccharides, diarylheptanoids, phenolic acids, phenolic glycoside and cyclic lipodepsipeptide have been hitherto isolated and characterized. The major bioactive compounds extracted from the rhizome of K. galanga were ethyl p-methoxycinnamate, ethyl cinnamate, kaempferol, kaempferide, kaempsulfonic acids, kaemgalangol A, xylose, cystargamide B and 3-caren-5-one. Various studies demonstrated that the K. galanga and its constituents possess several pharmacological activities like antimicrobial, antioxidant, amebicidal, analgesic, anti-inflammatory, anti-tuberculosis, anti-dengue, anti-nociceptive, anti-angiogenic, anticancer, hyperlipidemic, hypopigmentary, osteolysis, larvicidal, insecticidal and mosquito repellent, nematocidal, sedative, sniffing, vasorelaxant and wound healing.
CONCLUSION: Kaempferia galanga L. is a valuable medicinal plant which is used traditionally in India to treat a wide variety of ailments. A number of bioactive phytochemicals like esters, terpenoids, flavonoids, polysaccharides, diarylheptanoids, cyclic lipodepsipeptide, phenolic acids and glucoside have been isolated from the rhizomes of K. galanga by several researchers. These phytochemicals are highly bioactive and exhibit various pharmacological activities.
KEY FINDINGS: Majority of antimicrobials have been discovered from prokaryotes and those which are of eukaryotic origin are derived mainly from fungal and plant sources. With this in mind, it is important to note that pests, such as cockroaches come across pathogenic bacteria routinely, yet thrive in polluted environments. Other animals, such as snakes thrive from feeding on germ-infested rodents. Logically, such species must have developed an approach to protect themselves from these pathogens, yet they have largely been ignored as a potential source of antimicrobials despite their remarkable capability to fight disease-causing organisms.
SUMMARY: Animals living in polluted environments are an underutilized source for potential antimicrobials, hence it is believed that several novel bioactive molecule(s) will be identified from these sources to counter increasingly resistant bacterial infections. Further research will be necessary in the development of novel antimicrobial(s) from these unusual sources which will have huge clinical impact worldwide.