Evaluation of different solvents to extract antibacterial compounds from jalapeño peppers

Abstract

Chili peppers (Capsicum spp.) may possess antibacterial properties and have potential to be used in foods as antimicrobial. The complete chili pepper extract should be evaluated to determine which compounds are responsible for the antimicrobial activity. Extraction of compounds from the pepper is completed using a solvent. The type of solvent used for extraction influences which compounds are isolated, therefore the best extraction method needs to be determined. The purpose of this study was to identify which solvent is most successful at extracting unknown antibacterial compounds from jalapeño peppers. Fresh jalapeño peppers were chopped, weighed, and blended with a solvent (sterilized hot water, 70% methanol, 95% methanol, 70% ethanol, or 95% ethanol) at a 1:1 ratio (g/g) until the mixture was homogenized, followed by shaking for 15 min. The slurry was centrifuged; supernatant was removed and used for antibacterial testing against Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella enterica. The diameter of growth inhibition was measured and statistically evaluated using ANOVA to determine the extract with the greatest antimicrobial activity. Solvents were tested alone as a control. There was greater bacterial inhibition from extracts created with methanol and ethanol than hot water. Listeria monocytogenes was significantly more susceptible to the extracts than E. coli or Salmonella isolates. Each solvent extract was then analyzed using high‐performance liquid chromatography (HPLC) and fractions (A–G) were collected and used for subsequent disk diffusion analysis against L. monocytogenes. Fractions E and F (eluded between 20 and 30 min) exhibited the most antibacterial activity. There were no differences between solvents used (p = .05). Further investigation into specific compounds within these extracts will be completed in the future.

Antibacterial activity of jalapeño pepper (Capsicum annuum var. annuum) extract fractions against select foodborne pathogens

“…“Del Mar”) was prepared as described by Bacon et al. () using no solvent. Any extract that was not used immediately was stored at 4°C until use.…”

“…Extracts from Capsicum annuum fruit have been investigated to some extent, and antimicrobial properties have been reported with mixed results. Crude tissue extracts from several different C. annuum varieties have inhibited growth of species of Bacillus , Clostridium , Pseudomonas , Listeria , Salmonella , Staphylococcus , and Streptococcus (Bacon et al., ; Careaga et al., ; Cichewicz & Thorpe, ; Dorantes et al., ). Extract from jalapeno fruit, specifically, has inhibited Streptococcus pyogenes , Listeria monocytogenes , Clostridium sporogenes , and Clostridium tetani (Bacon et al., ; Cichewicz & Thorpe, ).…”

“…Crude tissue extracts from several different C. annuum varieties have inhibited growth of species of Bacillus , Clostridium , Pseudomonas , Listeria , Salmonella , Staphylococcus , and Streptococcus (Bacon et al., ; Careaga et al., ; Cichewicz & Thorpe, ; Dorantes et al., ). Extract from jalapeno fruit, specifically, has inhibited Streptococcus pyogenes , Listeria monocytogenes , Clostridium sporogenes , and Clostridium tetani (Bacon et al., ; Cichewicz & Thorpe, ). However, when trials were completed comparing results to a commercial capsaicin product (60% and 98% purity), there was no antimicrobial activity reported suggesting activity is not exclusively associated with the capsaicin in the pepper (Bacon et al., ; Cichewicz & Thorpe, ).…”

“…Extract from jalapeno fruit, specifically, has inhibited Streptococcus pyogenes , Listeria monocytogenes , Clostridium sporogenes , and Clostridium tetani (Bacon et al., ; Cichewicz & Thorpe, ). However, when trials were completed comparing results to a commercial capsaicin product (60% and 98% purity), there was no antimicrobial activity reported suggesting activity is not exclusively associated with the capsaicin in the pepper (Bacon et al., ; Cichewicz & Thorpe, ). Another study did, however, report that high concentrations of a commercial capsaicin were inhibitory against Bacillus subtilis , specifically (Molina‐Torres, Garcia‐Chávez, & Ramirez‐Chávez, ).…”

“…Our research group previously fractionated C. annum var. jalapeno extract to determine the best method for extraction and found that the fractions eluded between 20 and 30 min contained the most antimicrobial activity, especially against L. monocytogenes (Bacon et al., ). To our knowledge, there have been no other studies that have evaluated the fractions of C. annum var.…”