Roselle Calyx Research Articles

Extraction Characteristics of Anthocyanin from Roselle (Hibiscus sabdariffa L.) Calyces by Ultrasound-Assisted Extraction

Extraction Characteristics of Anthocyanin from Roselle (<i>Hibiscus sabdariffa L.</i>) Calyces by Ultrasound-Assisted Extraction

Antioxidant characteristics of extracts of Hibiscus sabdariffa calyces encapsulated with mesquite gum.

This study compared the stability of extracts of H. sabdariffa calyces microencapsulated with different concentrations of mesquite gum during storage. Dry Roselle calyces were mixed with 50:50 (v/v) ethanol:water solution to obtain 18°Bx concentrate. This Roselle extract concentrate was mixed with purified mesquite gum (100:1-100:5v/w). The Roselle extract concentrate-gum (RECG) was spray dried at inlet and outlet temperatures of 180±2 and 104±2.3°C, respectively, at an air flow rate of 38m3/h. Encapsulated Roselle powders (ERP) were analyzed for moisture content, total monomeric anthocyanins (differential pH), phenolic compounds (Folin and Ciocalteu method), antioxidant capacity (ABTS), and color parameters ([Formula: see text], and [Formula: see text]) after 5weeks and 1year of storage. Sorption properties (isotherms) and micrographs of powders were also obtained. The average yield of RECG powders was 15.27±0.81g/100mL. During storage, ERP showed average values of phenolic compounds, antioxidant capacity, and anthocyanins of 3.43±0.25g gallic acid equivalents/100g, 9.34±1.4g Trolox equivalents/100g, and 318.7±20.6mg cyanidin-O-glycoside/100g, respectively. Color parameters remained constant along the storage time.

Attachment of 13 Types of Foodborne Bacteria to Jalapeño and Serrano Peppers and Antibacterial Effect of Roselle Calyx Extracts, Sodium Hypochlorite, Colloidal Silver, and Acetic Acid against These Foodborne Bacteria on Peppers

Chili peppers are a very important crop in Mexico. However, these peppers have been associated with Salmonella infection outbreaks in the United States, and Salmonella and diarrheagenic Escherichia coli pathotypes have been isolated from jalapeño and serrano peppers in Mexico. To decrease microbial contamination of fruits and vegetables, chemical agents are commonly used; however, chemical agents used to eliminate pathogenic bacteria on vegetables have a limited antimicrobial effect. Roselle ( Hibiscus sabdariffa ) calyces have been reported to have an antimicrobial effect on pathogenic bacteria. In the present study, the antibacterial effect of four roselle calyx extracts (water, methanol, acetone, and ethyl acetate), sodium hypochlorite, colloidal silver, and acetic acid against foodborne bacteria was evaluated on contaminated jalapeño and serrano peppers. The 13 types of foodborne bacteria evaluated were Listeria monocytogenes , Shigella flexneri , Salmonella Typhimurium, Salmonella Typhi, Salmonella Montevideo, Staphylococcus aureus , E. coli O157:H7, five E. coli pathotypes (Shiga toxin producing, enteropathogenic, enterotoxigenic, enteroinvasive, and enteroaggregative), and Vibrio cholerae O1. All 13 types attached to both pepper types, with no significant differences in attachment between jalapeño and serrano peppers. Roselle calyx extract treatment resulted in a greater reduction in levels of all foodborne bacteria than did treatment with sodium hypochlorite, colloidal silver, and acetic acid on both pepper types. Roselle calyx extracts may be a useful for disinfection of chili peppers in the field, processing plants, restaurants, and homes.

Pengaruh Pemberian Fraksi Ekstrak Etanol Kelopak Bunga Rosella (Hibiscus sabdariffa L.) Terhadap Volume Urin Tikus Putih Jantan

Research on the effect of giving the fraction of ethanolic extracts of roselle calyx ( Hibiscus sabdariffa L.) to male white rats urine volume has been done, the fraction was given orally at a dose of n -hexane fraction of 95 mg/g BW, the fraction of ethyl acetate 145 mg/g BW and the fraction of the remaining 350 mg/g BW once a days for 7, 14 and 21. Result shows that the fraction of n -hexane giving 95 mg/g BW, fraction ethyl acetate of 145 mg/g BW, and the remaining fraction of 3450 mg/kg BW roselle calyx ( Hibiscus sabdariffa L.) can effect urine volume increased male white rats. Duration of the three fractions on days 7, 14 and 21 show a not significant increase in urine volume (P<0.05).

English

The dyeing potential of roselle (Hibiscus sabdarifa) extract variously extracted by boiling, steeping and ethanol solvent were evaluated with three dye fixatives (potassium aluminum sulphate (alum), tannic acid, and citric acid), to study their effects on cotton (100%), stone silk (60% silk:40% polyester) and polyester (100%) fabrics. Colourfastness to sunlight, washing, perspiration (acid and alkali) and rubbing (crocking) were studied on the individual fabrics as 1 &times; 4 factorial involving three dye extracts (1 dye source &times; three extraction methods) and three dye fixatives plus a non mordanted control in a completely randomized design (CRD) of three replications. Data on degree of fastness were generated as scores through 1 (excessive colour fade or stain) to 5 (no colour fade or stain) using Gray scale and fastness test rating scale (FTRS) evaluation instruments. Data were analyzed using descriptive statistics (means and standard deviations) and general linear model for factorial experiments of statistical package for social sciences (SPSS) version 16.0. Three null hypotheses were tested using analysis of variance (ANOVA). Treatment means were compared using Scheffe&rsquo;s test at 0.05 probability level. Findings include: Roselle calyces extracts showed reasonable colourfastness on cotton prototypes. The effects of dye extraction procedures did not significantly differ (p&gt;0.05) on the colourfastness of cotton prototypes to sunlight (p=0.33), washing (p=0.39), alkali perspiration (p=0.06) and dry rubbing (0.59). The effects of mordant/dye fixatives did not significantly differ (p&gt;0.5) on the colourfastness of cotton prototypes to washing (p=0.95) and rubbing or crocking (p=0.68), but differed significantly (p&lt;0.05) on colourfastness to sunlight (p=0.00), acid perspiration (p=0.00) and alkali (p=0.00). Tannic acid and alum mordant were the source of difference. Roselle calyces extracts exhibited much to excessive fade and stain of colour and poor fastness to all parameters tested except rubbing fastness. Key words: Fabric, colourfastness, dye fixatives, dye extraction, Roselle.

Behavior of thirteen foodborne bacteria on whole Hass avocado and potential of roselle calyx extracts as alternative disinfectant agents of avocado

AbstractThe behavior of thirteen foodborne bacteria onto whole Hass avocado and the antibacterial effect of Hibiscus sabdariffa calyx extracts, sodium hypochlorite, acetic acid, and colloidal silver against foodborne bacteria on contaminated avocado were investigated. Avocados were inoculated with foodborne bacteria: Listeria monocytogenes, Shigella flexneri, Staphylococcus aureus, Salmonella Typhimurium, S. Typhi, S. Montevideo, Escherichia coli O157:H7, non‐O157:H7‐Shiga toxin‐producing E. coli, enteropathogenic E. coli, enterotoxigenic E. coli, enteroinvasive E. coli, enteroaggregative E. coli, and Vibrio cholerae O1. The antibacterial effect of four roselle calyx extracts (water, methanol, acetone, and ethyl acetate), sodium hypochlorite, colloidal silver, and acetic acid against all foodborne bacteria were examined onto avocados. All foodborne bacteria successfully attached and survived onto avocado at least 20 days. The acetonic and methanolic roselle extracts caused a greater reduction (until 4‐log10 in some cases) in the concentration of all foodborne bacteria than sodium hypochlorite, colloidal silver, and acetic acid on contaminated avocados.Practical applicationsHass avocado have been associated with foodborne disease caused by Salmonella. The sodium hypochlorite and colloidal silver solution are widely used to disinfect fruit and vegetables in restaurants and home in Mexico. Even, the Health Secretariat of Mexico promotes their use as disinfectants of fruit and vegetables. However, a number of studies have shown that chemical agents used to eliminate pathogenic bacteria on fruits have a limited antimicrobial effect. Roselle calyx extracts are reported to have an antimicrobial effect. This study provides information on the significant impact of acetone and methanol roselle calyx extracts may be a potentially useful addition to disinfection procedures of avocado in the field and processing plants.

Efficacy of roselle (Hibiscus sabdariffa) calyx formulations against Escherichia coli O157:H7 during flume-washing of organic leafy greens

Foodborne outbreaks due to contaminated fresh produce, including organic leafy greens, have increased in the last twenty years. Several of these outbreaks have been associated with Escherichia coli O157:H7 infections. The limited availability of approved antimicrobial washes for organic leafy greens warrants the need to seek alternative approaches by the organic produce industry. The present study evaluated the use of roselle (Hibiscus sabdariffa) calyx formulations as flume-tank wash treatments for four types of organic leafy greens (iceberg and romaine lettuce, and mature and baby spinach). These formulations were prepared as either 10, 20, or 30% concentrations (v/v) of roselle aqueous extract or as 100% concentration (v/v) of roselle tea. Leafy greens were inoculated with a cocktail of 3 E. coli O157:H7 strains and washed with appropriate antimicrobial treatments. Treated leafy greens were tested for surviving E. coli O157:H7 populations on 0, 1, and 3 days. Results from the study indicated a 1.4-2.5 ...

Physicochemical and sensory properties of pineapple flavoured roselle powders

AbstractThis study was carried out to determine the physicochemical and sensory properties of blends of roselle and pineapple powders. The blends were produced by adding powder from natural pineapple to the powder of roselle calyces in the proportion of 15, 20 and 25%. The proximate composition, vitamin C, pH, total soluble solids, bulk density, reconstitution index, particle size, titratable acidity and reducing sugars were determined using standard methods. The proximate compositions of the samples were in the range of 4.94–6.57% (protein), 63.41–67.22% (carbohydrate), 2.31–2.48% (fat), 9.23–10.34% (fibre), 8.04–9.93% (ash) and 7.44–8.09% (moisture). The vitamin C contents ranged between 67.23 and 76.88 mg/100 g. The pH, total soluble solids and reducing sugar increased significantly (p < 0.05) while the titratable acidity, bulk density, reconstitution index and mass mean diameter decreased significantly (p < 0.05) with increase in addition of pineapple powder to roselle powder. Based on sensory evaluat...

Image Cone Models Detect Roselle Calix (Hibiscus sabdariffa) Weight Remotely

Roselle (Hibiscus sabdariffa var. sabdariffa race ruber) is cultivated for its human health benefits. Roselle calyxes are dried to extend their shelf life while trying to maintain their antioxidant properties. Small-scale Mexican producers require driers of 1 ton per day to avoid calyx pathogen contamination. Prior to this, a 1-calyx prototype had to be built in order to study energy consumption per flower, best calyx position during drying and the effect of airflow recirculation. Producers want to know when the calyx has reached the final relative humidity (RH) to stop the drying process; so a remote weighting system was developed. Three image processing algorithms were proposed based on the geometry of a truncated cone that resembles the roselle calyx. The images were acquired with an iPhone running with a timer application. High correlations between the surface model and calyx weight were found for both fresh and dried calyxes (R2 values of 0.98 and 0.99 respectively). Geometrical dimensions remained constant as the drying process took place, such that inter-calyx height was consistently 33% of calyx height and waist height was 73% of calyx height. Images taken from a 100 kg drier helped to foresee the problems that could be encountered to obtain the calyx parameters. The use of the geometric dimensions reduced the number of measurements required per calyx to two: inter-calyx waist distance and inter-calyx diameter. A high correlation of 0.97 was obtained between calyx weight and the predicted volume with the surface model using those two measurements.

EFFECT OF ROSELLE CALYX EXTRACT ON GINGIPAIN ACTIVITY, PRODUCTION OF INFLAMMATORY CYTOKINES, AND ORAL BACTERIAL MORPHOLOGY

This study to investigate the effect of roselle calyx extract on gingipain activity, production of inflammatory cytokines, and oral bacterial morphology. The inhibitory effect of roselle calyx extract (RCE) on Arg- (Rgp) and Lys-gingipain (Kgp) was evaluated using synthetic substrate colorimetric assay with a 96-well microtiter plate. RCE with various concentrations was tested for determination of interleukin (IL)-6 and IL-8 produced from KB cells stimulated with heat-inactivated P. gingivalis. The production of IL-6 and IL-8 was quantified using an ELISA kit. The morphological alterations in cells of S. mutans and P. gingivalis after treatment with RCE were studied using scanning electron microscopy (SEM). RCE could inhibit both Rgp (90%) and Kgp (70%) activities significantly at concentrations lower than the minimum inhibitory concentration (MIC) (2.2 mg/mL). Furthermore, the production of IL-6 and IL-8 from KB cells stimulated with P. gingivalis was significantly inhibited by RCE at 6 h after exposure, in a dose-dependent manner. After treatment with RCE, the morphological alterations were observed in cells of S. mutans and P. gingivalis by using SEM. The ability of RCE to inhibit gingipain activity and production of inflammatory cytokines indicates that RCE could be considered for prevention and clinical treatment for periodontitis.

Antibacterial activity of roselle calyx extracts, sodium hypochlorite, colloidal silver and acetic acid against multidrug‐resistant salmonella serotypes isolated from coriander

AbstractMultidrug‐resistant Salmonella serotypes (M‐RSs) were isolated from coriander, and an analysis done of the antibacterial activity of roselle calyx extracts against any of the identified strains. One‐hundred coriander samples were collected from markets. Salmonella was isolated from the coriander samples by culture procedure. Susceptibilities to sixteen antibiotics were determined for the isolated Salmonella strains by standard test. The antibacterial effect of four roselle extracts (water, methanol, acetone and ethyl acetate), sodium hypochlorite, acetic acid and colloidal silver against M‐RS isolates was evaluated on contaminated coriander. Thirty‐one Salmonella strains were isolated from 23% of coriander samples. Identified Salmonella serotypes were typhimurium, typhi and montevideo. All isolated strains exhibited resistance to at least three antibiotics. Roselle extracts caused a greater reduction in concentration of M‐RSs than the sodium hypochlorite, colloidal silver and acetic acid on contaminated coriander. Roselle calyx extracts may be a potentially useful addition to disinfection procedures of coriander.Practical applicationsThe colloidal silver solution (Microdyn) and sodium hypochlorite are widely used to disinfect fruit and vegetables in restaurants and home in Mexico. Even, the Health Secretariat of Mexico promotes their use as disinfectants of fruit and vegetables. Roselle (Hibiscus sabdariffa) calyces are reported to have an antimicrobial effect on pathogenic bacteria. There is no information about the reduction in the concentration of multidrug‐resistant Salmonella serotypes (M‐RSs) on coriander by typical disinfectant solutions, such as colloidal silver and sodium hypochlorite or roselle calyx extracts. M‐RSs were isolated from coriander purchased in public markets in Mexico and challenged with roselle calyx extracts, sodium hypochlorite, colloidal silver and acetic acid. The roselle extracts caused a greater reduction in the concentration of M‐RSs than sodium hypochlorite, acetic acid and colloidal silver on coriander. Roselle calyx extracts are a potentially useful addition to disinfection procedures of coriander in the field, processing plants, restaurants and homes.

Effect of Roselle calyces extract on the chemical and sensory properties of functional cupcakes

Roselle calyces (RC) are a major crop for export and used to make a common drink in Egypt. Dried RC are commercially available and appreciated to obtain concentrated extracts which might be used in the food and pharmaceutical industries for color and heath benefits. The objective of this research was to determine the chemical and the sensory properties of cupcakes formulated with Roselle calyces extract (RCE). Proximate analysis, anthocyanins, ascorbic acid, titrable acidity, % retaining of anthocyanins, color and sensory evaluations were done. RC cupcakes had high sensory scores (P<0.05) compared to control cupcakes. The parameter a* was significantly red in the RC cupcakes compared to control cupcakes along with 77% retaining of anthocyanins. The consumption of 100g of the RC cupcakes would provide 465mg/100g dry matter anthocyanin that is more than 2 folds of the minimum average of the daily intake of anthocyanins for Americans, along ∼1/3 of the daily dietary fiber intake to achieve fiber adequacy according to the Scientific Advisory Committee on Nutrition. RC cupcake can be a functional food and would have a “clean” label with cost effective advantage.

English

The study evaluated the acceptability of 100% cotton fabric treated with dye extracted from roselle (Hibiscus sabdariffa) calyces based on its phytochemical compositions and organoleptic attributes. A quasi-experimental design was adopted by the study and was carried out at the University of Nigeria Nsukka, Enugu State, Nigeria. The study population comprised of 41 panelists made up of 17 Lecturers and 24 Postgraduate students drawn from the university. Spectrophotometric and gravimetric methods were adopted for the quantitative analysis of phytochemical constituents of extracts from roselle calyces. Questionnaire was used to collect data on the organoleptic attributes and acceptability of cotton fabric treated with roselle dye and data were analyzed using descriptive statistics including percentages, means, and standard deviation. A null hypothesis was tested at 0.05 level of significance using t-test. The following phytochemical components were present in roselle dye extract: carotenoid (1.96%), flavonoid (0.02%), lutein (0.03%), polyphenol (0.12%), tannin (0.88%) per 100 g of roselle calyces. Organoleptic attributes of cotton fabric treated with dye extracted from roselle calyces identified include: Fairly warm maroon colour hue, fairly light value, fairly brilliant chroma, smooth and fairly soft textures, odourless and even shade colour which were all accepted as good attributes of dye on fabrics by both categories of evaluators. There were no significant differences (P>0.05) in the mean rating responses of both categories of evaluators on the acceptability of the organoleptic attributes of cotton fabric treated with roselle dye. The null hypothesis was accepted at 0.05 level of significance. Roselle dye has good organoleptic attributes and could be used for 100% cotton fabric colouration. Key words: Phytochemical, organoleptic attributes, roselle dye, cotton fabric.

Design and Evaluation of Geared Rollers for a Roselle Harvester

Roselle calyces, which are the consumable commercial part of the plant, are mainly hand-harvested in Mexico. Harvesting machines use an electric or gasoline motor to turn rollers that pull in branches full of roselle flowers; electric motors are cleaner and reduce calyx pollution. Water squeezed from the branches as they pass through the harvester reduces traction on the rubber-coated rollers. Geared rollers with Nylamid teeth were designed, manufactured, and installed in a roselle harvester so that water extracted from the branches could run off through the roller grooves. Four 23-tooth Nylamid rollers were evaluated for an increase in harvest productivity over 18-tooth rollers. Productivity reached 64.8 kg h -1 for variety Nayarit and 62.9 kg h -1 for variety Sudan. Calyx quality during harvest was better with 23-tooth rollers, with no calyx damage for variety Nayarit. Varieties White Sudan and Colima 5 detached perfectly dry capsules from calyces using 23-tooth rollers. The force exerted by the rollers to pull the branch was measured and reached 323 N for 3.7 cm thick branches. Branch water loss accounted for 2 to 4 g depending on branch thickness.

Anthocyanins from roselle extract arrest cell cycle G2/M phase transition via ATM/Chk pathway in p53-deficient leukemia HL-60 cells.

Cell cycle regulation is an important issue in cancer therapy. Delphinidin and cyanidin are two major anthocyanins of the roselle plant (Hibiscus sabdariffa). In the present study, we investigated the effect of Hibiscus anthocyanins (HAs) on cell cycle arrest in human leukemia cell line HL-60 and the analyzed the underlying molecular mechanisms. HAs extracted from roselle calyces (purity 90%) markedly induced G2/M arrest evaluated with flow cytometry analysis. Western blot analyses revealed that HAs (0.1-0.7 mgmL-1 ) induced G2/M arrest via increasing Tyr15 phosphorylation of Cdc2, and inducing Cdk inhibitors p27 and p21. HAs also induced phosphorylation of upstream signals related to G2/M arrest such as phosphorylation of Cdc25C tyrosine phosphatase at Ser216, increasing the binding of pCdc25C with 14-3-3 protein. HAs-induced phosphorylation of Cdc25C could be activated by ATM checkpoint kinases, Chk1, and Chk2. We first time confirmed that ATM-Chk1/2-Cdc25C pathway as a critical mechanism for G2/M arrest in HAs-induced leukemia cell cycle arrest, indicating that this compound could be a promising anticancer candidate or chemopreventive agents for further investigation. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1290-1304, 2017.

Effect of agitated bed drying on the retention of phenolic compounds, anthocyanins and antioxidant activity of roselle (Hibiscus sabdariffa L.)

SummaryAn agitated fluidised bed dryer was employed to dry lixiviated roselle (Hibiscus sabdariffa L.) calyxes. The effects of operational drying variables on the chemical attributes such as the retention of monomeric anthocyanins (MA), phenolic compounds, polymeric colour, antioxidant activity and drying rate were analysed. Drying curves showed only decreasing falling rate period. To determine the kinetic parameters, the drying data were fitted to a Page's model, based on the moisture content ratio vs. the drying time; the k values ranged from 1.58 × 10−5 to 6.28 × 10−2 s−1. The different drying conditions showed significant differences in the chemical parameters. When processing wet feeds, as lixiviated roselle calyxes, the mechanical assisted fluidisation can be considered as an innovative concept.

Evaluation of the effects of roselle (Hibiscus sabdariffa L.) on oxidative stress and serum levels of lipids, insulin and hs-CRP in adult patients with metabolic syndrome: a double-blind placebo-controlled clinical trial.

Roselle (Hibiscus sabdariffa L.) is a plant with antihyperlipidemic and antihypertensive effects. This study aimed to evaluate the effects of roselle calyces on the serum levels of lipids and insulin, inflammation, and oxidative stress in patients with metabolic syndrome (MetS). Forty adult patients with MetS were randomly assigned to receive either 500 mg of H. sabdariffa calyx powder or placebo once daily for 4 weeks. Systolic and diastolic blood pressures (SBP and DBP) and BMI (body mass index) as well as fasting serum levels of glucose (FPG; fasting plasma glucose), insulin, lipoproteins, triglycerides (TG), high-sensitivity C-reactive protein (hs-CRP), and malondialdehyde (MDA) were determined pre- and post-intervention and compared. H. sabdariffa significantly reduced serum TG (p=0.044) and SBP (p=0.049) compared to placebo. All other variables were not significantly affected by the interventions. Daily consumption of 500 mg of H. sabdariffa L. calyx powder can decrease SBP and serum TG in MetS patients.

The Effect of Ethanolic Extract of Roselle (Hibiscuss sabdariffa L) on Increasing SOD Activity

Free radicals were reactive species caused oxidation of lipids membrane and DNA. Superoxide dismutase (SOD) is one of the primary antioxidants to inhibit free radicals. The purpose of this study was to determine the effect of ethanol extract of roselle calyx on SOD enzyme activity of the Sprague Dawley (SD) rats induced by 7.12-dimethylbenzen[a]anthracene (DMBA). The animals age of four weeks divided in to five groups, groups I were normal group. Group II is the negative control group only induced by DMBA 75 mg/kgBW; and group III ,IV ,and V were treatment groups that treated by ethanolic extract of roselle calyx at dose of 10, 50 and 100 mg/kgBW/day for 7 days. After treatment with roselle, animals were induced by DMBA 75 mg/kgBW. On day 8 after DMBA induction, animals were fasted for 16 hours and blood was collected to measured SOD activity. Data were analyzed using One Way Analysis Of Variance (ANOVA) and LSD (P &amp;lt;0.05). The result showed the significancies on increasing of SOD activity at 10 mg/kgBW (50.87±1.98), 50 mg/kgBW (69.98±3.58) and 100 mg/kgBW (73.01±6.95) compared with DMBA (43.74±1.95) (p&amp;lt;0,05).

The Effect of Ethanolic Extract of Roselle (Hibiscuss sabdariffa L) on Increasing SOD Activity

Free radicals were reactive species caused oxidation of lipids membrane and DNA. Superoxide dismutase (SOD) is one of the primary antioxidants to inhibit free radicals. The purpose of this study was to determine the effect of ethanol extract of roselle calyx on SOD enzyme activity of the Sprague Dawley (SD) rats induced by 7.12-dimethylbenzen[a]anthracene (DMBA). The animals age of four weeks divided in to five groups, groups I were normal group. Group II is the negative control group only induced by DMBA 75 mg/kgBW; and group III ,IV , and V were treatment groups that treated by ethanolic extract of roselle calyx at dose of 10, 50 and 100 mg/kgBW/day for 7 days. After treatment with roselle, animals were induced by DMBA 75 mg/kgBW. On day 8 after DMBA induction, animals were fasted for 16 hours and blood was collected to measured SOD activity. Data were analyzed using One Way Analysis Of Variance (ANOVA) and LSD (P &amp;lt;0.05). The result showed the significancies on increasing of SOD activity at 10 mg/kgBW (50.87±1.98), 50 mg/kgBW (69.98±3.58) and 100 mg/kgBW (73.01±6.95) compared with DMBA (43.74±1.95) (p&amp;lt;0,05).

Antibacterial effect of roselle extracts (Hibiscus sabadariffa), sodium hypochlorite and acetic acid against multidrug-resistant Salmonella strains isolated from tomatoes.

Antibiotic-resistant Salmonella strains were isolated from saladette and red round type tomatoes, and an analysis done of the antibacterial activity of roselle calyx extracts against any of the identified strains. One hundred saladette tomato samples and 100 red round tomato samples were collected from public markets. Each sample consisted of four whole tomatoes. Salmonella was isolated from the samples by conventional culture procedure. Susceptibility to 16 antibiotics was tested for the isolated Salmonella strains by standard test. The antibacterial effect of four roselle calyx extracts (water, methanol, acetone and ethyl acetate), sodium hypochlorite and acetic acid against antibiotic-resistant Salmonella isolates was evaluated on contaminated tomatoes. Twenty-four Salmonella strains were isolated from 12% of each tomato type. Identified Salmonella serotypes were Typhimurium and Typhi. All isolated strains exhibited resistance to at least three antibiotics and some to as many as 12. Over contaminated tomatoes, the roselle calyx extracts produced a greater reduction (2-2·6 log) in antibiotic-resistant Salmonella strain concentration than sodium hypochlorite and acetic acid. The presence of multidrug-resistant Salmonella in vegetables is a significant public health concern. Multidrug-resistant Salmonella strains were isolated from raw tomatoes purchased in public markets in Mexico and challenged with roselle Hibiscus sabdariffa calyx extracts, sodium hypochlorite and acetic acid. On tomatoes, the extracts caused a greater reduction in the concentration of antibiotic-resistant Salmonella strains than sodium hypochlorite and acetic acid. Roselle calyx extracts are a potentially useful addition to disinfection procedures of raw tomatoes in the field, processing plants, restaurants and homes.