Anticariogenic Activity of Three Essential Oils from Brazilian Piperaceae.

The current trend toward using natural food additives, cosmetics, and medicines has motivated industries to substitute synthetic compounds for natural products. Essential oils (EOs) from medicinal plants are a well-known source of chemical compounds that display several interesting biological activities, including antimicrobial action. In this study, we investigated the antibacterial activity of EOs extracted from three Piperaceae species collected in the Brazilian Amazon region against a representative panel of cariogenic bacteria. The minimum inhibitory concentration (MIC) of the essential oils extracted from Peperomia pellucida (PP-EO), Piper marginatum (PM-EO), and Piper callosum (PC-EO) was determined against Streptococcus mutans, S. mitis, S. sanguinis, S. salivarius, S. sobrinus, Enterococcus faecalis, and Lactobacillus casei by using the microplate microdilution method. PM-EO, PC-EO, and PP-EO displayed antibacterial activity against all the tested cariogenic bacteria. PM-EO displayed the best inhibitory activity, with MIC values ranging from 50 to 500 µg/mL. The lowest MIC values were obtained for PM-EO against S. mitis (MIC = 75 µg/mL), Lactobacillus casei (MIC = 50 µg/mL), and S. mutans (MIC = 50 µg/mL). Gas chromatography mass spectrometry (GC-MS) analysis allowed the chemical composition of all the EOs to be identified. The main constituents of PM-EO, PC-EO, and PP-EO were 3,4-(methylenedioxy)propiophenone, α-pinene, and dillapiole, respectively. Finally, the compounds that were exclusively detected in PM-EO are highlighted. Our results suggest that PM-EO may be used in products for treating dental caries and periodontal diseases.

Chemical composition and insecticidal activity of the essential oils of Piper marginatum , Piper callosum and Vitex agnus-castus.

During grain storage, a considerable amount of product is lost because of insects, such as Zabrotes subfasciatus. Currently, to mitigate these risks, studies are searching for plants with potential for the control of agricultural pests, also known as botanical insecticides. In this study, the fumigant toxicity of the essential oils of Piper callosum (PC-EO), Piper marginatum (PM-EO) and Vitex agnus-castus (VA-EO) against Zabrotes subfasciatus was investigated. The essential oils of PC-EO, PM-EO and VA-EO were analysed by gas chromatography (GC-MS), and the major components were 3,4-methylenedioxypropiophenone (10.4%), bicyclogermacrene (10.1%) and germacrene D (9.9%) for PM-EO; safrol (29.3%) for PC-EO; and 1,8-cineol (23.8%) for VA-EO. In fumigation tests, VA-EO killed 100% Zabrotes subfasciatus at a concentration of 0.004 µL/L air after 24 h of treatment, whereas PC-EO and PM-EO at 0.01 µL/L air caused 100% Z. subfasciatus mortality after 48 h. The VA-EO sample provided the lowest LD50 after 24 h (0.17 µL/L air), followed by PC-EO (0.78 µL/L air) and PM-EO (1.17 µL/L air). These results demonstrate that the essential oils of these species can be an alternative to control pests in stored products. This is the first report of the fumigant potential of these species against Z. subfasciatus.

Probing the antioxidant potential of phloretin and phlorizin through a computational investigation.

The structures and energetics of two dihydrochalcones (phloretin and its glycoside phlorizin) were examined with density functional theory, using the B3LYP, M06-2X, and LC-ω PBE functionals with both the 6-311G(d,p) and 6-311 + G(d,p) basis sets. Properties connected to antioxidant activity, i.e., bond dissociation enthalpies (BDEs) for OH groups and ionization potentials (IPs), were computed in a variety of environments including the gas-phase, n-hexane, ethanol, methanol, and water. The smallest BDEs among the four OH groups for phloretin (three for phlorizin) were determined (using B3LYP/6-311 + G(d,p) in water) to be 79.36 kcal/mol for phloretin and 79.98 kcal/mol for phlorizin while the IPs (at the same level of theory) were obtained as 139.48 and 138.98 kcal/mol, respectively. By comparing with known antioxidants, these values for the BDEs indicate both phloretin and phlorizin show promise for antioxidant activity. In addition, the presence of the sugar moiety has a moderate (0-6 kcal/mol depending on functional) effect on the BDEs for all OH groups. Interestingly, the BDEs suggest that (depending on the functional chosen) the sugar moiety can lead to an increase, decrease, or no change in the antioxidant activity. Therefore, further experimental tests are encouraged to understand the substituent effect on the BDEs for phloretin and to help determine the most appropriate functional to probe BDEs for dihydrochalcones.

Chemical Composition and Antibacterial Activity of the Essential Oil of Vitex agnus-castus L. (Lamiaceae).

Abnormal multiplication of oral bacteria causes dental caries and dental plaque. These diseases continue to be major public health concerns worldwide, mainly in developing countries. In this study, the chemical composition and antimicrobial activity of the essential oil of Vitex agnus-castus leaves (VAC‒EO) collected in the North of Brazil against a representative panel of cariogenic bacteria were investigated. The antimicrobial activity of VAC-EO was evaluated in terms of its minimum inhibitory concentration (MIC) values by using the broth microdilution method in 96-well microplates. The chemical constituents of VAC-EO were identified by gas chromatography (GC‒FID) and gas chromatography‒mass spectrometry (GC‒MS). VAC‒EO displayed some activity against all the investigated oral pathogens; MIC values ranged from 15.6 to 200 µg/mL. VAC-EO had promising activity against Streptococcus mutans (MIC= 15.6 µg/mL), Lactobacillus casei (MIC= 15.6 µg/mL), and Streptococcus mitis (MIC= 31.2 µg/mL). The compounds 1,8-cineole (23.8%), (E)-ß-farnesene (14.6%), (E)-caryophyllene (12.5%), sabinene (11.4%), and α-terpinyl acetate (7.7%) were the major chemical constituents of VAC‒EO. VAC-EO displays antimicrobial activity against cariogenic bacteria. The efficacy of VAC-EO against S. mutans is noteworthy and should be further investigated.

Chemical Composition and Antibacterial Activity of the Essential Oil of Vitex agnus-castus L. (Lamiaceae)

ABSTRACT Abnormal multiplication of oral bacteria causes dental caries and dental plaque. These diseases continue to be major public health concerns worldwide, mainly in developing countries. In this study, the chemical composition and antimicrobial activity of the essential oil of Vitex agnus-castus leaves (VAC‒EO) collected in the North of Brazil against a representative panel of cariogenic bacteria were investigated. The antimicrobial activity of VAC-EO was evaluated in terms of its minimum inhibitory concentration (MIC) values by using the broth microdilution method in 96-well microplates. The chemical constituents of VAC-EO were identified by gas chromatography (GC‒FID) and gas chromatography‒mass spectrometry (GC‒MS). VAC‒EO displayed some activity against all the investigated oral pathogens; MIC values ranged from 15.6 to 200 μg/mL. VAC-EO had promising activity against Streptococcus mutans (MIC= 15.6 μg/mL), Lactobacillus casei (MIC= 15.6 μg/mL), and Streptococcus mitis (MIC= 31.2 μg/mL). The compounds 1,8-cineole (23.8%), (E)-β-farnesene (14.6%), (E)-caryophyllene (12.5%), sabinene (11.4%), and α-terpinyl acetate (7.7%) were the major chemical constituents of VAC‒EO. VAC-EO displays antimicrobial activity against cariogenic bacteria. The efficacy of VAC-EO against S. mutans is noteworthy and should be further investigated.

Pyrimidine alkaloids from Eudistoma vannamei

Abstract Methanolic extracts of the Brazilian endemic ascidian Eudistoma vannamei have been extensively studied for their cytotoxic activity against several human cancer cell lines. Previous work reported the occurrence of purine derivatives and staurosporine alkaloids as the major nitrogen-containing compounds. In this study, we report the occurrence of three pyrimidine alkaloids in addition to cholesterol, sitosterol and stigmasterol.

Structure elucidation and anticancer activity of 7-oxostaurosporine derivatives from the Brazilian endemic tunicate Eudistoma vannamei.

The present study reports the identification of two new staurosporine derivatives, 2-hydroxy-7-oxostaurosporine (1) and 3-hydroxy-7-oxostaurosporine (2), obtained from mid-polar fractions of an aqueous methanol extract of the tunicate Eudistoma vannamei, endemic to the northeast coast of Brazil. The mixture of 1 and 2 displayed IC50 values in the nM range and was up to 14 times more cytotoxic than staurosporine across a panel of tumor cell lines, as evaluated using the MTT assay.

Antileukemic effects of Didemnum psammatodes (Tunicata: Ascidiacea) constituents.

Chemical investigation of the methanolic extract of the ascidian Didemnum psammatodes has led to the identification of fourteen known compounds: three methyl esters (methyl myristate, methyl palmitate and methyl stearate), four steroids (cholesterol, campesterol, stigmasterol and beta-sitosterol), two fatty acids (palmitic acid and stearic acid), three glyceryl ethers {(1,2-propanediol, 3-(heptadecyloxy), batyl alcohol and 1,2-propanediol, 3-[(methyloctadecyl)oxy]} and two nucleosides (thymidine and 2'-deoxyguanosine). Their structures were proposed by NMR and comparison with literature data and GC analysis in comparison with authentic sample. The cytotoxic activity of these compounds was evaluated against human leukemia cell line panel using the MTT assay. The mixture of the three methyl esters was the most active group of compounds, showing antiproliferative and cytotoxic effects. Further studies on their mode of action suggest that these activities are connected with inhibition of DNA synthesis and induction of both necrosis and apoptosis.

Cytotoxic activity of a dichloromethane extract and fractions obtained from Eudistoma vannamei (Tunicata: Ascidiacea).

This study consists of the bioassay-guided fractionation of the dichloromethane extract from Eudistoma vannamei and the pharmacological characterization of the active fractions. The dried hydromethanolic extract dissolved in aqueous methanol was partitioned with dichloromethane and chromatographed on a silica gel flash column. The anti-proliferative effect was monitored by the MTT assay. Four of the latest fractions, numbered 14 to 17, which held many chemical similarities amongst each other, were found to be the most active. The selected fractions were tested for viability, proliferation and death induction on cultures of HL-60 promyeloblastic leukemia cells. The results suggested that the observed cytotoxicity is related to apoptosis induction.