The in vitro Antibacterial Activity and Brine Shrimp Toxicity of Manihot esculenta var. Sri Pontian (Euphorbiacea) Extracts

Comparative toxicity, phytochemistry, and use of 53 Philippine medicinal plants

The study compares the toxicity of 53 selected medicinal plants commonly used in the Philippines to treat various diseases. It uses as a benchmark Vitex negundo L., which was approved by the Philippine Food and Drug Administration as an herbal drug for cough and asthma after passing clinical trials for safety and efficacy. The methods were chosen for their simplicity and accessibility even for resource-limited laboratories. Extracts (95 % ethanol) of the medicinal parts of the plants were (1) chemically profiled using qualitative phytochemical tests that detect the presence of key classes of bioactive compounds; and (2) evaluated for toxicity using the brine shrimp (Artemia sp.) lethality assay (BSLA). General phytochemical screening revealed the presence of tannins in 50 plant extracts, alkaloids in 43, glycosides in 33, flavonoids in 31, steroids in 21, triterpenoids in 20, anthraquinones in 10, and saponins in 8. Extracts from eight plants had LC50 values lower than the potassium dichromate control (approximately 12 μg/mL) and were considered highly toxic; extracts from 21 plants had LC50 values between 12 μg/mL and 100 μg/mL and were considered moderately toxic; extracts from 19 plant extracts, including Vitex negundo and some common vegetables, had LC50 values between 100 μg/mL and 500 μg/mL, and were considered mildly toxic and likely to have reasonable safety margins; five plant extracts, including common vegetables, had LC50 values above 500 μg/mL and were considered essentially nontoxic. No apparent correlation could be found between toxicity and chemical diversity or a specific class of phytochemicals present. Our findings may serve as a guide for herbal drug and nutraceutical development, especially in prioritizing plants for more detailed safety studies.

Antioxidant Activities of Methanol Extracts of Thirteen Cameroonian Antibacterial Dietary Plants

This study falls within the search for alternative solutions to problems related to diseases associated with oxidative stress. It involved the evaluation of antioxidant activities extracts from thirteen antibacterial Cameroonian food plants, namely, P. nigrum, A. cruentus, L. sativa, S. edule, S. nigrum, V. amygdalina, A. hybridus, V. hymenolepis, L. capensis, M. esculenta, C. melo, T. occidentalis, and T. triangulare. The thirteen plant extracts with a broad spectrum of antibacterial activity all showed total reducing powers ranging between 2.41 and 27.81 AAE (mg ascorbic acid equivalents per gram of dried extract) and total phenol contents between 2.65 and 35.03 GAE (mg of gallic acid equivalents per gram of dried extract) of dry extract. Except for extracts of L. capensis, the other 12 extracts showed flavonoid contents ranging between 0.29 and 5.99 RE (rutin equivalents per gram of dried extract). All 13 plant extracts also showed free radical scavenging activity against DPPH· with IC50 ranging between 1.65 and 310.52 μg/ml, while 12 of these extracts exhibited inhibitory activity against NO· radical (IC50 ranging from 19.77 to 157.72 μg/ml). Statistically insignificant positive correlations ( $p>0.5$ ) were found between antibacterial activities of these plants and their antioxidant activities. The different results of this study provide scientific evidence for the use of these antibacterial food plants in the control of different conditions associated with oxidative stress.

A purely green synthesis of silver nanoparticles using Carica papaya, Manihot esculenta, and Morinda citrifolia: synthesis and antibacterial evaluations

Green procedure for synthesizing silver nanoparticles (AgNPs) is currently considered due to its economy and toxic-free effects. Several existing works on synthesizing AgNPs using leaves extract still involve the use of physical or mechanical treatment such as heating or stirring, which consume a lot of energy. To extend and explore the green extraction philosophy, we report here the synthesis and antibacterial evaluations of a purely green procedure to synthesize AgNPs using Carica papaya, Manihot esculenta, and Morinda citrifolia leaves extract without the aforementioned additional treatment. The produced AgNPs were characterized using the ultraviolet-visible spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and antibacterial investigations. For antibacterial tests, two bacteria namely Escherichia coli and Bacillus cereus were selected. The presently employed method has successfully produced spherical AgNPs having sizes ranging from 9 to 69 nm, with plasmonic characteristics ranging from 356 to 485 nm, and energy-dispersive X-ray peak at approximately 3 keV. In addition, the smallest particles can be produced when Manihot esculenta leaves extract was applied. Moreover, this study also confirmed that both the leaves and synthesized AgNPs exhibit the antibacterial capability, depending on their concentration and the bacteria type.

Treating leishmaniasis in Amazonia: A review of ethnomedicinal concepts and pharmaco-chemical analysis of traditional treatments to inspire modern phytotherapies

ETHNOPHARMACOLOGICAL RELEVANCE

Cutaneous and mucocutaneous leishmaniasis are neglected tropical diseases that occur in all intertropical regions of the world. Amazonian populations have developed an abundant knowledge of the disease and its remedies. Therefore, we undertook to review traditional antileishmanial plants in Amazonia and have developed new tools to analyze this somewhat dispersed information.

MATERIAL AND METHODS

A literature review of traditional remedies for cutaneous/mucocutaneous leishmaniasis in the Amazon was conducted and the data obtained was used to calculate distribution indexes designed to highlight the most relevant uses in Amazonia. The cultural distribution index represents the distribution rate of a given taxon among different cultural groups and was calculated as the ratio of the number of groups using the taxon to the total number of groups cited. The geographical distribution index allowed us to quantify spatial distribution of a taxon's uses in Amazonia and was calculated geometrically by measuring the average distance between the points where uses have been reported and the barycenter of those points. The general distribution index was defined as an arithmetic combination of the previous two and provides information on both cultural and spatial criteria.

RESULTS

475 use reports, concerning 291 botanical species belonging to 83 families have been gathered depicted from 29 sources. Uses concern 34 cultural groups. While the use of some taxa appears to be Pan-Amazonian, some others are clearly restricted to small geographical regions. Particular attention has been paid to the recipes and beliefs surrounding treatments. Topical application of the remedies dominated the other means of administration and this deserves particular attention as the main treatments against Neotropical leishmaniasis are painful systemic injections. The data set was analyzed using the previously defined distribution indexes and the most relevant taxa were further discussed from a phytochemical and pharmacological point of view.

CONCLUSIONS

The Amazonian biodiversity and cultural heritage host a fantastic amount of data whose systematic investigation should allow a better large-scale understanding of the dynamics of traditional therapies and the consequent discovery of therapeutic solutions for neglected diseases. Distribution indices are indeed powerful tools for emphasizing the most relevant treatments against a given disease and should be very useful in the meta-analysis of other regional pharmacopeia. This focus on renowned remedies that have not yet benefitted from extended laboratory studies, could stimulate future research on new treatments of natural origin for leishmaniasis.

Antibacterial activities of the methanol extracts of ten Cameroonian vegetables against Gram-negative multidrug-resistant bacteria

BACKGROUND

Many edible plants are used in Cameroon since ancient time to control microbial infections. This study was designed at evaluating the antibacterial activities of the methanol extracts of ten Cameroonian vegetables against a panel of twenty nine Gram negative bacteria including multi-drug resistant (MDR) strains.

METHODS

The broth microdilution method was used to determine the Minimal Inhibitory Concentrations (MIC) and the Minimal Bactericidal Concentrations (MBC) of the studied extracts. When chloramphenicol was used as a reference antibiotic, the MICs were also determined in the presence of Phenylalanine-Arginine β-Naphtylamide (PAβN), an efflux pumps inhibitor (EPI). The phytochemical screening of the extracts was performed using standard methods.

RESULTS

All tested extracts exhibited antibacterial activities, with the MIC values varying from 128 to 1024 mg/L. The studied extracts showed large spectra of action, those from L. sativa, S. edule, C. pepo and S. nigrum being active on all the 29 bacterial strains tested meanwhile those from Amaranthus hybridus, Vernonia hymenolepsis, Lactuca.carpensis and Manihot esculenta were active on 96.55% of the strains used. The plant extracts were assessed for the presence of large classes of secondary metabolites: alkaloids, anthocyanins, anthraquinones, flavonoids, phenols, saponins, steroids, tannins and triterpenes. Each studied plant extract was found to contain compounds belonging to at least two of the above mentioned classes.

CONCLUSION

These results confirm the traditional claims and provide promising baseline information for the potential use of the tested vegetables in the fight against bacterial infections involving MDR phenotypes.

In vitro antioxidant activity, phytochemical screening, cytotoxicity and total phenolic content in extracts of Caesalpinia pulcherrima (Caesalpiniaceae) pods

Caesalpinia pulcherrima L. Swartz (Caesalpiniaceae) is an ornamental plant also used as a common medicinal plant in India, Taiwan and South-East Asian countries. Majority of the diseases/disorders are mainly linked to oxidative stress due to free radicals. The aims of this study were to screen for phytochemical constituents, evaluate cytotoxicity, in vitro antioxidant activity and estimation of total phenolic content of extracts of pods of Caesalpinia pulcherrima. Phytochemical analysis revealed the presence of tannins, flavonoids, steroids and alkaloids. Brine Shrimp Lethality (BSL) bioassay was used to investigate the cytotoxic effects. The LC50(microg mL(-1)) values obtained for extracts as 750 microg mL(-1) for petroleum ether extract, 800 microg mL(-1) for chloroform extract and 900 microg mL(-1) for methanol extract. The total phenolic content of the methanolic extract was 38.04% w/w, equivalent to gallic acid. Petroleum ether, chloroform and methanolic extracts of Caesalpinia pulcherrima and standard ascorbic acid were found to be scavenger of DPPH radical with an IC50 of 124.75, 112.08, 54.34 and 13.86 microg mL(-1), respectively. Methanolic extract was good scavenger of DPPH radical. Petroleum ether, chloroform, ethyl acetate soluble fraction of methanolic extracts of pods of Caesalpinia pulcherrima and ascorbic acid were found to be scavenger of nitric oxide radical with an IC50 of 93.32, 65.12, 54.83 and 12.59 microg mL(-1), respectively. Ethyl acetate soluble fraction was found to be good scavenger of nitric oxide radical. Our conclusion provides support that the crude extracts of C. pulcherrima is a probable source of natural antioxidants and this justified its uses in folkloric medicines.

Alkaloid presence and brine shrimp (Artemia salina) bioassay of medicinal species of eastern Nicaragua

We used an alkaloid test and a brine shrimp bioassay to assess the bioactivity of the medicinal plants used by eastern Nicaraguan healers in traditional medicine. Ethnomedicinal uses were obtained from interviews of traditional healers. Aqueous extracts derived from 30 species of angiosperms were assayed for the presence of alkaloids and toxicity. Species tested are distributed in 30 genera and 21 families. Of the 30 species tested for alkaloids with Dragendorff's reagent, 29 contained alkaloids. Toxicological analysis was conducted using the brine shrimp lethal assay (BSLA). Biological activity using BSLA was recorded as the median lethal concentration (LC50) that kills 50% of the larvae within 24 h of contact with the aqueous plant extracts. The LC50 of the shrimp was less than 2500 microg/mL for 3 (10%) species, 2500-5000 microg/mL for 9 (30%), 5001-7500 microg/mL for 7 (23%), 7501-10000 microg/mL for 3 (10%), and greater than 10000 microg/mL for 8 (27%) of the species. The members of the orders Santales and Rubiales in general contained species with greater toxicity than any other group. Struthanthus cassythoides (Struthanthus cassythoides Millsp.(Loranthaceae)). (LC50 1574 microg/mL) and Alibertia edulis (Rich.) A. Rich. (Rubiaceae) (LC50 1741 microg/mL) were the most toxic.