Antimicrobial activities of medicinal plants used in folklore remedies in south-western

In south-western part of Nigeria Psidium guajava and Mangifera indica are commonly used for herbal preparations in the treatment of toothache, gastrointestinal disorders, dynsentery, diarrhoea, sore gums and sore throats. This has, therefore, led to the investigation of the antimicrobial activities of methanolic extracts of P. guajava and M. indica. Fifteen different bacterial isolates comprising of both Gram negative and Gram positive organisms were used. The results show that P. guajava and M. indica extracts exhibited antimicrobial activities at a concentration of 20 mg/ml. The zones of inhibitionexhibited by P. guajava extract ranged between 12 mm and 30 mm while that of M. indica varied between 11 and 28 mm. The minimum inhibitory concentration (MIC) exhibited by P. guajava extract against the tested organisms ranged between 0.313 and 0.625 mg/ml. On the other hand MIC exhibited by M. indica extract varied between 1.25 and 10.0 mg/ml. Overall, P. guajava extract show more antimicrobial activity than M. indica extract against tested organism

In vitro antilisterial properties of crude aqueous and nhexane extracts of the husk of Cocos nucifera

The in vitro antilisterial activities and time kill regimes of crude aqueous and n-hexane extracts of the husk fiber of Cocos nucifera were assessed. The aqueous extracts were active against 29 of the 37 test Listeria isolates while the n-hexane extracts were active against 30. The minimum inhibitory concentrations (MICs) of all the susceptible bacteria ranged between 0.6 and 2.5 mg/ml for the aqueous fraction and between 0.6 and 5.0 mg/ml for the n-hexane extract. The average log reduction in viable cell count in the time kill assay ranged between 0.32 Log10 and 3.2 Log10 cfu/ml after 4 h of interaction, and between 2.6 Log10 and 4.8 Log10 cfu/ml after 8 h interaction in 1 × MIC and 2 × MIC (aqueous extract); and between 2.8 Log10 and 4.8 Log10 cfu/ml after 4 h of interaction, and 3.5 Log10 to 6.2 Log10 cfu/ml after 8 h interaction in 1 × MIC and 2 × MIC for the n-hexane extract. The extract was bactericidal against one of the test bacteria at 1 × MIC and against three of the test bacteria at 2 × MIC for the 8 h interaction period for the aqueous extract, while for the n-Hexane fraction; the extract was bactericidal against all the five test bacteria at both MICs after the 8 h interaction period. We suggested that the crude aqueous and n-hexane extracts of the husk of C. nucifera could be bacteriostatic or bactericidal depending on the time of exposure and concentration.Key words: Cocos nucifera, n-hexane extract, aqueous extract, minimum inhibitory concentration, time-kill

Antimicrobial activity of extracts and a germacranolidetype sesquiterpene lactone from Tithonia diversifolia leaf extract

The in vitro antimicrobial activity of the hexane, ethyl acetate and methanol extracts of the leaf of Tithonia diversifolia, and one sesquiterpene lactone 1 isolated from the ethyl acetate extract wasstudied. Of the fourteen strains of bacteria used, the ethyl acetate extract was the most active, showing inhibitory activity against five Gram +ve and two Gram –ve organisms. This was followed by the hexane extract and then methanol. The ethyl acetate fractions (TDE 2 – TDE 5, TDE 7, TDE 8 and TDE 10) showed varying degrees of inhibitory activity. The sesquiterpene lactone 1 showed activity against all the tested microorganisms, except Staphylococcus aureus and Bacillus cereus (MICs = 15.6 – 62.5mg/ml for most stains). All the extracts, fractions and compound 1 showed activity against the fungusCandida albicans. The results of the present study indicate that the non-polar leaf extract of T.diversifolia could be useful in the treatment of some disease conditions and the sesquiterpene lactone 1 could be a good candidate as a phytotherapeutic agent against some bacterial infection

Antimicrobial and antioxidant activity of kaempferol rhamnoside derivatives from Bryophyllum pinnatum

Abstract Background Bryophyllum pinnatum (Lank.) Oken (Crassulaceae) is a perennial succulent herb widely used in traditional medicine to treat many ailments. Its wide range of uses in folk medicine justifies its being called "life plant" or "resurrection plant", prompting researchers' interest. We describe here the isolation and structure elucidation of antimicrobial and/or antioxidant components from the EtOAc extract of B. pinnatum. Results The methanol extract displayed both antimicrobial activities with minimum inhibitory concentration (MIC) values ranging from 32 to 512 μg/ml and antioxidant property with an IC50 value of 52.48 μg/ml. Its partition enhanced the antimicrobial activity in EtOAc extract (MIC = 16-128 μg/ml) and reduced it in hexane extract (MIC = 256-1024 μg/ml). In addition, this process reduced the antioxidant activity in EtOAc and hexane extracts with IC50 values of 78.11 and 90.04 μg/ml respectively. Fractionation of EtOAc extract gave seven kaempferol rhamnosides, including; kaempferitrin (1), kaempferol 3-O-α-L-(2-acetyl)rhamnopyranoside-7-O-α-L-rhamnopyranoside (2), kaempferol 3-O-α-L-(3-acetyl)rhamnopyranoside-7-O-α-L-rhamnopyranoside (3), kaempferol 3-O-α-L-(4-acetyl)rhamnopyranoside-7-O-α-L-rhamnopyranoside (4), kaempferol 3-O-α-D- glucopyranoside-7-O-α-L-rhamnopyranoside (5), afzelin (6) and α-rhamnoisorobin (7). All these compounds, except 6 were isolated from this plant for the first time. Compound 7 was the most active, with MIC values ranging from 1 to 2 μg/ml and its antioxidant activity (IC50 = 0.71 μg/ml) was higher than that of the reference drug (IC50 = 0.96 μg/ml). Conclusion These findings demonstrate that Bryophyllum pinnatum and some of its isolated compounds have interesting antimicrobial and antioxidant properties, and therefore confirming the traditional use of B. pinnatum in the treatment of infectious and free radical damages.</p

Microarray analysis revealed different gene expression patterns in HepG2 cells treated with low and high concentrations of the extracts of Anacardium occidentale shoots

In this study, the effects of low and high concentrations of the Anacardium occidentale shoot extracts on gene expression in liver HepG2 cells were investigated. From MTT assays, the concentration of the shoot extracts that maintained 50% cell viability (IC50) was 1.7 mg/ml. Cell viability was kept above 90% at both 0.4 mg/ml and 0.6 mg/ml of the extracts. The three concentrations were subsequently used for the gene expression analysis using Affymetrix Human Genome 1.0 S.T arrays. The microarray data were validated using real-time qRT–PCR. A total of 246, 696 and 4503 genes were significantly regulated (P < 0.01) by at least 1.5-fold in response to 0.4, 0.6 and 1.7 mg/ml of the extracts, respectively. Mutually regulated genes in response to the three concentrations included CDKN3, LOC100289612, DHFR, VRK1, CDC6, AURKB and GABRE. Genes like CYP24A1, BRCA1, AURKA, CDC2, CDK2, CDK4 and INSR were significantly regulated at 0.6 mg/ml and 1.7 mg but not at 0.4 mg/ml. However, the expression of genes including LGR5, IGFBP3, RB1, IDE, LDLR, MTTP, APOB, MTIX, SOD2 and SOD3 were exclusively regulated at the IC50 concentration. In conclusion, low concentrations of the extracts were able to significantly regulate a sizable number of genes. The type of genes that were expressed was highly dependent on the concentration of the extracts used

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

Background: Many patients with COVID-19 have been treated with plasma containing anti-SARS-CoV-2 antibodies. We aimed to evaluate the safety and efficacy of convalescent plasma therapy in patients admitted to hospital with COVID-19. Methods: This randomised, controlled, open-label, platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]) is assessing several possible treatments in patients hospitalised with COVID-19 in the UK. The trial is underway at 177 NHS hospitals from across the UK. Eligible and consenting patients were randomly assigned (1:1) to receive either usual care alone (usual care group) or usual care plus high-titre convalescent plasma (convalescent plasma group). The primary outcome was 28-day mortality, analysed on an intention-to-treat basis. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936. Findings: Between May 28, 2020, and Jan 15, 2021, 11558 (71%) of 16287 patients enrolled in RECOVERY were eligible to receive convalescent plasma and were assigned to either the convalescent plasma group or the usual care group. There was no significant difference in 28-day mortality between the two groups: 1399 (24%) of 5795 patients in the convalescent plasma group and 1408 (24%) of 5763 patients in the usual care group died within 28 days (rate ratio 1·00, 95% CI 0·93–1·07; p=0·95). The 28-day mortality rate ratio was similar in all prespecified subgroups of patients, including in those patients without detectable SARS-CoV-2 antibodies at randomisation. Allocation to convalescent plasma had no significant effect on the proportion of patients discharged from hospital within 28 days (3832 [66%] patients in the convalescent plasma group vs 3822 [66%] patients in the usual care group; rate ratio 0·99, 95% CI 0·94–1·03; p=0·57). Among those not on invasive mechanical ventilation at randomisation, there was no significant difference in the proportion of patients meeting the composite endpoint of progression to invasive mechanical ventilation or death (1568 [29%] of 5493 patients in the convalescent plasma group vs 1568 [29%] of 5448 patients in the usual care group; rate ratio 0·99, 95% CI 0·93–1·05; p=0·79). Interpretation: In patients hospitalised with COVID-19, high-titre convalescent plasma did not improve survival or other prespecified clinical outcomes. Funding: UK Research and Innovation (Medical Research Council) and National Institute of Health Research

In vitro antimicrobial and phytochemical properties of crude extract of stem bark of Afzelia africana (Smith)

Afzelia africana is used in folklore remedies for the treatment of diarrhoea, gastrointestinal disorders and gonorrhoea among other ailments; hence we assessed the in vitro antimicrobial activities of thisimportant medicinal plant. Thirty bacterial isolates as well as four fungal isolates were tested in this study. The crude extract of the stem bark of the plant exhibited antimicrobial activities at a concentration of 25 mg/ml against twenty-one of the bacterial isolates, (i.e. 72.41% of the tested isolates) comprising both Gram positive and Gram negative strains. The zones of inhibition exhibited by the extract against the test bacterial species ranged between 13 and 22 mm. The Minimum Inhibitory Concentrations (MIC) of the extract vary between 1.56 and 12.50 mg/ml while the Minimum Bactericidal Concentration (MBC) ranged between 3.13 and 25.00 mg/ml. However, the extract lacked activity against all four tested fungal species. Phytochemical assay revealed the presence of alkaloids, tannins, flavonoids and saponins in the extract. We conclude that the stem bark of A. africana is a promising candidate as source of new antibacterial compounds

The bioactive potentials of two medicinal plants commonly used as folklore remedies among some tribes in West Africa

Jatropha curcas and Newboulda laevis are medicinal plants used for the treatment of ailments such as diarrhoea, dysentery, sexually  ransmitted diseases, jaundice and several other diseases caused bymicro-organisms. The antibacterial activities of the leaves of the plants were assessed against a panel of selected bacterial pathogens. Methanolic leaf extracts of J. curcas and N. laevis exhibited antibacterial activity against eight of the thirteen tested bacterial isolates at a final concentration of 20 mg/ml. The zones of inhibition exhibited by J. curcas ranged between 12 and 17 mm while that of N. laevis varied between 10 and 23 mm. The minimum inhibitory concentration of J. curcas extract ranged between 0.625 and 10.00 mg/ml, while that of N. laevis extract varied between 0.313 and 10 mg/ml. The standard antibiotic – streptomycin had MIC values of between 0.0313 and 0.0625 mg/ml. Phytochemical compounds present in the extract of J. curcas include alkaloids, saponins, steroids and tannins, while those present in N. laevis extract includes alkaloids, flavonoids and tannins

The bioactive and phytochemical properties of Garcinia kola (Heckel) seed extract on some pathogens

In vitro antimicrobial activities of crude extract of Garcinia kola was investigated against some bacterial isolates comprising of both Gram-positive and Gram-negative organisms. The methanolic crude extract exhibited significant inhibitory action against eleven out of fifteen bacterial isolates tested at a final concentration of 20 mg/ml. The zones of inhibition exhibited by the extract against the tested organisms ranged between 10 and 23 mm, while the zones of inhibition exhibited by streptomycin and tetracycline used as standard antibiotics ranged between 15 and 25 mm; 12 and 25 mm respectively. On the other hand, the minimum inhibitory concentrations exerted by the extract against the bacterial isolates ranged between 0.079 and 5.00 mg/ml while the ranged exhibited by streptomycin was between 0.0157 and 0.50 mg/ml. The plant extract compared favourably with the two standard antibiotics used in this study. The following phytochemical compounds were present in the plant extract: flavonoids, tannins, cardiac glycoside, saponins, steroids and reducing sugars