Antibacterial activity of various leaf extracts of Merremia emarginata

An In Vitro Evaluation of the Antibacterial Efficacy of Solanum xanthocarpum Extracts on Bacteria From Dental Plaque Biofilm

OBJECTIVE

The focus of research has recently shifted toward developing herbal-based medicines due to the emerging bacterial resistance and side effects of antibiotics. Solanum xanthocarpum (Sx) is a medicinal plant with potent pharmacological properties. This study aimed to evaluate the antibacterial activity of its crude extracts on bacteria isolated from dental plaque in patients with gingivitis.

MATERIALS AND METHODS

Aqueous, ethyl acetate, hexane, chloroform, and ethanolic extracts were prepared from Sx. Dental plaque samples were collected from patients with plaque-induced gingivitis. Disk diffusion assay was performed to determine the antibacterial activity of the extracts at concentrations of 25 mg/ml, 50 mg/ml, and 75 mg/ml with ampicillin 200 mg/ml as a positive control. The minimum inhibitory concentration (MIC) of the aqueous extract was also evaluated by broth dilution test against bacteria isolated from dental plaque biofilm.

RESULTS

The antibacterial activity was estimated by measuring the zones of inhibition through the disc diffusion method. The Kruskal Wallis with Dunn post hoc test performed for intergroup comparison between the various extracts showed a statistically significant difference in inhibition of bacterial growth between 25 mg/ml and 75 mg/ml concentrations. There was no significant difference between the 75 mg/ml Sx concentration and the positive control. In addition, the MIC was elucidated to be 0.625 g/ml, at which there was maximum inhibition of bacterial growth.

CONCLUSION

The Sx extract exhibited antibacterial activity against periodontal pathogens. Thus, it can be concluded that optimum concentrations of Sx could be used in therapeutic strategies to prevent and manage periodontal diseases.

Research Progression of the Genus Merremia: A Comprehensive Review on the Nutritional Value, Ethnomedicinal Uses, Phytochemistry, Pharmacology, and Toxicity

The genus Merremia Dennst. ex Endl. (Convolvulaceae) is a rich source of structurally diverse phytochemicals with therapeutic relevance. This review presents the first comprehensive, up-to-date information and research progression on the nutritional value, ethnomedicinal uses, phytochemistry, pharmacological activities, and toxicity of the genus Merremia. Using the key search term “Merremia”, relevant documents and information were retrieved from electronic databases. Relevant documents were uploaded in RStudio with installed bibliometric software packages and used for data retrieval, tabulation, and network visualization. Bibliometric analysis revealed that ca. 55% of the studies related to Merremia were published in the last decade, which can be grouped into four thematic areas: (i) drug formulation, (ii) taxonomy, (iii) chemical analysis, and (iv) treatment of diseases. Ethnomedicinal uses, phytochemistry, and biological activities studies showed that species in the genus are promising medicinal plants with various pharmaceutical potentials. However, clinical studies to validate the efficacy of the reported bioactivities and the mechanisms underlying the various activities are lacking and should constitute a future research focus. Additionally, reports on the nutritional and antinutritional constituents of Merremia species revealed that the species meet high nutritional quality criteria for animals and are therefore suitable for inclusion in livestock diets. The few available investigations on toxicity indicated that most Merremia species are safe for human and animal use but not with prolonged chronic administration.

Chemical, antimicrobial, and molecular characterization of mortiño (Vaccinium floribundum Kunth) fruits and leaves

Fruits and leaves of Vaccinium spp. are known for their high content of bioactive compounds, but the chemical and biological characteristics of mortiño (Vaccinium floribundum Kunth) have not been fully described. In this study, the levels of polyphenols, antioxidant capacity, anthocyanins, antimicrobial activity, and genetic variability were determined in mortiño plants. The Folin-Ciocalteu's, ABTS scavenging, pH differential, and well diffusion methods were used to evaluate the levels of polyphenols, antioxidant capacity, anthocyanins, and antimicrobial activity, respectively. The genetic variability was evaluated by sequencing of the matK and rbcl DNA regions. Polyphenol content was up to 229.81 mg gallic acid equivalents/100 g, the average antioxidant capacity was 11.01 mmol Trolox equivalents/100 g, and anthocyanin content was up to 1,095.39 mg/100 g. Mortiño extracts significantly inhibited the growth of Gram-negative bacteria including Burkholderia gladioli, Burkholderia cepacia, Salmonella Typhimurium, Vibrio parahaemolyticus, Vibrio harveyi, Vibrio vulnificus, Escherichia coli, and Pseudomona aeruginosa, as well as Gram-positive bacteria such as Probionibacterium propionicum, Staphylococcus aureus, and Enterococcus faecalis showing greater inhibition halos than those produced by the antibiotic ampicillin. A polymorphic nucleotide was found in position 739 of the matK region. This study shows the potential of mortiño for the food and pharmaceutical industries.

Seed Germination and Seedling Characteristic of <I>ipomoea</I> and <I>Merremia </I>(Convolvulaceae) in Lambayeque (Peru)

BACKGROUND AND OBJECTIVE

Studies were undertaken to determine the effects of in vivo germination of mechanically scarified with and without sandpaper, chemically scarified with H2SO4 for 40 min and without H2SO4 and in vitro germinated with sandpaper and with sandpaper and GA3 seeds of ipomoea and Merremia in the Lambayeque region and surrounding areas (Peru).

MATERIALS AND METHODS

Seeds of 16 species of ipomoea and 3 species of Merremia collected from Lambayeque (Peru) were germinated under in vivo and in vitro conditions and measured the angle of divergence of seedlings and the data were analysed by ANOVA.

RESULTS

in the in vivo germination process, mechanical and chemical scarification caused an increase in germination and in the in vitro germination process mechanical scarification with sandpaper and GA3 also caused an increase in germination. Seedling emergence was observed and recorded and found not to fit the classical models of hypogeal and epigeal emergence and in the seedling morphology the degree of apical cleft of paracotyledonary leaves and the angle of divergence between the two lobes of a paracotyledon were determined. The length of the apical cleft was highly correlated (r = 0.81) with the angle of divergence.

CONCLUSION

Convolvulaceae is the most advanced family that produces seeds with physical dormancy (water-impermeable seed coat).

In vitro control of Staphylococcus aureus (NCTC 6571) and Escherichia coli (ATCC 25922) by Ricinus communis L

OBJECTIVE

To evaluate antibacterial activity of hot and cold ethanol and methanol leaf extracts of Ricinus communis L (R. communis) against Staphylococcus aureus (S. aureus) (NCTC 6571) and Escherichia coli (E. coli) (ATCC 25922).

METHODS

Leaf powder of R. communis L. was extracted with hot (in Soxhlet) and cold ethanol and methanol, separately. The antibacterial activity of the extracts was determined by agar well diffusion and macro broth dilution methods. The extracts were also subjected to phytochemical analysis.

RESULTS

All the four test extracts showed inhibition on both S. aureus and E. coli. Hot and cold ethanol extracts revealed significantly (P<0.05) higher inhibition on S. aureus than methanol extracts, and the hot ethanol extract had the lowest minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values (5 mg/mL and 10 mg/mL, respectively). E. coli was highly inhibited by hot extracts of both ethanol and methanol with the MIC and MBC of 40 mg/mL and 80 mg/mL, respectively. Phytochemical analysis revealed the presence of saponins, cardiac glycosides, tannins, flavonoids and terpenoids in all test extracts.

CONCLUSIONS

This study demonstrates that the hot and cold methanol and ethanol extracts are potential sources for control of S. aureus and E. coli. Especially, the hot and cold extracts of ethanol are more inhibitive against S. aureus even at lower concentration. Further study is needed to identify the specific bioactive compounds, their mode of action and their nontoxic nature in vivo condition.

In vitro antioxidant and antimicrobial activities of Merremia emarginata using thio glycolic acid-capped cadmium telluride quantum dots

This study was undertaken to evaluate the antioxidant potential of an aqueous extract from Merremia emarginata leaves because this plant has a very high flavonoid and phenol content. The in vitro antioxidant activity was measured by diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid (ABTS), superoxide anion scavenging assay and lipid peroxidation activity; the total reducing capability of the plant extract indicates that this plant is a source for natural antioxidants. Furthermore, we investigated thio glycolic acid-capped cadmium telluride quantum dots (TGA-CdTe QDs) as fluorescent probes to study the antioxidant activity of the M. emarginata extract through fluorescence quenching. The antimicrobial activity was also investigated using a disc diffusion method and fluorescence microscopy. The TGA-CdTe QDs and M. emarginata complex could provide antimicrobial activity through a reactive oxygen species pathway and/or microbial endocytosis through an electrostatic attraction. Based on our findings, we suggest that the QDs act as potential probes for the in vitro antioxidant and antimicrobial activities. In addition, their cooperative effect with the plant extract indicates that QDs could be used as nanocarriers to enhance the antimicrobial capability. Further in vivo studies on the photolabelling of antioxidants with QDs will provide insights into the mechanistic pathways of secondary metabolites against various degenerative diseases.

Antimicrobial activity and essential oils of Curcuma aeruginosa, Curcuma mangga, and Zingiber cassumunar from Malaysia

OBJECTIVE

To analyze the chemical composition of the essential oils of Curcuma aeruginosa (C. aeruginosa), Curcuma mangga (C. mangga), and Zingiber cassumunar (Z. cassumunar), and study their antimicrobial activity.

METHODS

Essential oils obtained by steam distillation were analyzed by gas chromatography-mass spectrometry (GC-MS). The antimicrobial activity of the essential oils was evaluated against four bacteria: Bacillus cereus (B. cereus), Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Pseudomonas aeruginosa (P. aeruginosa); and two fungi: Candida albicans (C. albicans) and Cyptococcus neoformans (C. neoformans), using disc-diffusion and broth microdilution methods.

RESULTS

Cycloisolongifolene, 8,9-dehydro formyl (35.29%) and dihydrocostunolide (22.51%) were the major compounds in C. aeruginosa oil; whereas caryophyllene oxide (18.71%) and caryophyllene (12.69%) were the major compounds in C. mangga oil; and 2,6,9,9-tetramethyl-2,6,10-cycloundecatrien-1-one (60.77%) and α-caryophyllene (23.92%) were abundant in Z. cassumunar oil. The essential oils displayed varying degrees of antimicrobial activity against all tested microorganisms. C. mangga oil had the highest and most broad-spectrum activity by inhibiting all microorganisms tested, with C. neoformans being the most sensitive microorganism by having the lowest minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values of 0.1 μL/mL. C. aeruginosa oil showed mild antimicrobial activity, whereas Z. cassumunar had very low or weak activity against the tested microorganisms.

CONCLUSIONS

The preliminary results suggest promising antimicrobial properties of C. mangga and C. aeruginosa, which may be useful for food preservation, pharmaceutical treatment and natural therapies.

Antimicrobial activity of mangrove plant (Lumnitzera littorea)

OBJECTIVE

To investigate the antimicrobial activities of n-hexane, ethyl acetate and methanol extracts of the leaves of Lumnitzera littorea (L. littorea) against six human pathogenic microbes.

METHODS

The antimicrobial activity was evaluated using disc diffusion and microdilution methods.

RESULTS

The antimicrobial activities of the crude extracts were increased with increasing the concentration. It is clear that n-hexane extract was the most effective extract. Additionally, Gram positive Bacillus cereus (B. cereus) appear to be the most sensitive strain while Pseudomonas aeruginosa (P. aeruginosa) and the yeast strains (Candida albicans (C. albicans) and Cryptococcus neoformans (C. neoformans)) appear to be resistance to the tested concentrations since no inhibition zone was observed. The inhibition of microbial growth at concentration as low as 0.04 mg/mL indicated the potent antimicrobial activity of L. littorea extracts.

CONCLUSIONS

The obtained results are considered sufficient for further study to isolate the compounds responsible for the activity and suggesting the possibility of finding potent antibacterial agents from L. littorea extracts.

Antibacterial activity of selected ethnomedicinal plants from South India

OBJECTIVE

To screen the antimicrobial potential of three ethnomedicinal plants Chassalia curviflora Thw. (C. curviflora), Cyclea peltata Hook. F. & Thomson (C. peltata) and Euphorbia hirta L (E. hirta) used in folk medicines in Aarukani hills Kani tribe, Tamil Nadu, India against human bacterial pathogens.

METHODS

Antibacterial efficacy was performed by disc diffusion method against the pathogens viz., Escherichia coli (E. coli) (ATCC 35218), Staphylococcus aureus (S. aureus) (ATCC 6538), Salmonella typhi (S. typhi) (MTCC 733), Proteus vulgaris (P. vulgaris), Proteus mirabilis (P. mirabilis) and Streptococcus pyogenes (S. pyogenes) and incubated for 24 h at 37 °C.

RESULTS

The maximum degree of antibacterial activity was observed in C. peltata followed by C. curviflora. While E. hirta showed comparatively low degree of antibacterial activity. The methanolic extract of C. peltata showed the antibacterial activity against three pathogens viz., S. pyogenes, P. vulgaris and E. coli with the inhibition zones 12 mm, 10 mm and 9 mm, respectively. hexane extracts of C. peltata also showed the antibacterial activity against two selected pathogens viz., P. vulgaris and P. mirabilis with 15 mm and 12 mm of inhibition zones. All the three different concentrations (0.25, 0.50 & 0.75 mg/mL) of methanolic extract of C. peltata show the inhibitory effect on the three susceptible bacteria S. pyogenes, P. vulgaris and E. coli with the maximum inhibition in the highest concentration (0.75 mg/mL). The methanolic and hexane extracts of C. curviflora exhibited the antibacterial activity against only one bacterium each i.e. P. vulgaris and S. typhi with the maximum zone of inhibition 13 and 11 mm respectively. The methanolic and hexane extracts of E. hirta exhibited the antibacterial activity against only one bacterium i.e. S. pyogenes with the maximum zone of inhibition 13 and 11 mm respectively.

CONCLUSIONS

The present investigation revealed that the C. curviflora, C. peltata and E. hirta are potentially good source of antibacterial agents and demonstrates the importance of such plants in traditional medicines.