Antifungal activity of three different varieties of Capsicum annuum against clinical isolates of Candida species
Tropical Diseases, Travel Medicine and Vaccines volume 9, Article number: 9 (2023)
Acquired resistance to antifungal agents is rising among Candida species. Herbal extracts including Capsicum annum extracts have biological profits, which can be employed to overcome drug resistance in fungal species. The present study investigated the efficacy of different varieties of C. annum extracts against Candida species.
Aqueous and alcoholic extracts of three different varieties of C. annum were prepared using the succulent method. Total values for compound extracts of C. annum var. cayenne, C. annum var. cayenne cultivar sabzevari, and C. annum var. cerasiforme were 43, 42, and 38 g, respectively. The clinical Candida isolates including C. albicans (n = 13), C. dubliniensis (n = 2), C. parapsilosis (n = 2), and C. tropicalis (n = 1); and reference strains of C. albicans (TIMML 1292 and TIMML 183), C. krusei (TIMML 1321), C. parapsilosis (TIMML 2201), and C. tropicalis (TIMML 731) were examined based on the M27-A3 guideline.
Aqueous and alcoholic extracts of Capsicum annum showed a minimum inhibitory concentration (MIC) range of more than 512 µg/ml against clinical and reference strains of Candida. There was no justifiable difference between the effects of these extracts on Candida species.
Both aqueous and alcoholic extracts of Capsicum annum could not exert a significant effective impact on clinical and reference strains of Candida. The difference in pepper spiciness did not show a significant role against Candida isolates. However, their possible effects might be different among other yeasts or filamentous fungi.
Candida species are kind of yeast fungi that are normal flora at the same time causing wide variety of infections from cutaneous to visceral. These Infections have become more frequent and common due to the increase in the use of systemic antibiotics, chemotherapy, corticosteroids, etc. [1,2,3]. The use of antibiotics disrupts the population of bacteria. This disruption results in an increase in the fungal normal flora population that can be a cause of endogen infection. Most of these infections are caused by C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, and C. krusei [2, 4]. Nowadays, it is notable that non-albicans Candida species have become more opportunistic pathogens in individuals . Multidrug-resistant Candida species have become a serious concern, therefore scientists express more interest in natural products such as medicinal plants or essential oils, and their antibacterial or antifungal activities [6, 7]. Herbal extracts and their derivatives have been studied as treatments for bacterial and fungal infections. For example, Curcumin is proven to have antifungal activity against fungal agents [8,9,10]. Assessing the antimicrobial susceptibility of clinical isolates helps to evaluate the effectiveness of metabolites in these medicinal plants against human pathogens [6, 11]. It is essential to determine the antifungal effects of herbal plants against common invasive Candida species since there is not enough evidence about their in vitro activity against Candida species. Capsicum annuum is cultivated throughout some countries like Iran and Turkey which can be used as a vegetable or condiment . It is known for its high nutritional values such as a wide range of vitamins, minerals, phytochemicals, and dietary fiber, thus it can decrease micronutrient deficiencies . As plants produce pathogenesis-related (PR) proteins against pathogen attack, it is justifiable to assume their antifungal activities . For instance, P14a, P14b, and P14c are isolated from tomato leaves with antifungal effects against phytophthora infestans . As a result, both aqueous and alcoholic extracts of C. annum were effective against bacteria like Vibrio cholerae, Staphylococcus aureus, and Salmonella typhimurium [12, 16]. However, the alcoholic extract showed greater antibacterial effects than aqueous . Moreover, studies showed C. annum as an antioxidant and cytotoxic resource, proving by radical scavenging activity and the MTT assay . Based on the fact that there were no comprehensive antifungal studies on C. annum extracts and to overcome drug resistance, this study evaluated the effects of both aqueous and alcoholic extracts of this plant against various Candida species.
This study was approved by the Ethics Committee (ethics code: IR.MUMS.MEDICAL.REC.1399.454).
The antifungal effects of aqueous and alcoholic extracts of C. annum has been evaluated against 18 Candida clinical isolates obtained from bronchoalveolar lavage (BAL) specimens of hospitalized children with pulmonary disorders referred to a specialized pediatric Hospital, Mashhad, Iran, including C. albicans (n = 13), C. dubliniensis (n = 2), and C. parapsilosis (n = 2), and C. tropicalis (n = 1), alongside 5 Candida reference strains including C. albicans (TIMML 1292, and TIMML 183), C. krusei (TIMML 1321), C. parapsilosis (TIMML 2201), and C. tropicalis (TIMML 731). All clinical isolates were identified by the Vitek MS (bioMérieux, Marcy-L'Etoile, France) and Multiplex PCR . The antifungal susceptibility testing was conducted according to the clinical and laboratory standards institute (CLSI) M27-A3 guidelines. Both aqueous and alcoholic extracts of C. annum were prepared referring to the Soxhlet method previously approved by our research group . Peppers were cultivated, collected, and authenticated by Anbari’s agricultural seed company. The herbarium number for each plant was provided as No.13529 for C. annum var. cayenne, No.13544 for C. annum var. cayenne cultivar sabzevari, and No.13588 for C. annum var. Cerasiforme. After transferring fruits to the laboratory, they were dried at room temperature and ground. Fifty grams of each powder was percolated in 1000 ml of 70% ethanol to make a 70% aqueous alcoholic soxhlet extract. It was then placed in the soxhlet apparatus for 72 h. To remove the solvent, the extracts were put in a glass plate on a boiling pan . A part of dried C. annum was subjected to solvent–solvent extraction for three fractions, namely, n-butanol fraction (NBF), ethyl acetate fraction (EAF), and aqueous fraction (AQF). In this method, C. annum var. cayenne, C. annum var. cayenne cultivar sabzevari, and C. annum var. Cerasiforme yielded 43%, 42%, and 38% extracts, respectively. After obtaining the compound extracts, aqueous and alcoholic fractions of them were prepared and kept at -20 °C until use.
All Candida isolates were sub-cultured on sabouraud dextrose agar (SDA, Merk, Germany) and incubated at 35 °C for 2 days. The inclusion criteria are the colonies of Candida that approved by the Vitek MS (bioMérieux, Marcy-L'Etoile, France) and Multiplex PCR  and the exclusion criteria are the specimen that haven’t grown in 24-48 h or contaminated by saprophytic fungi. After incubation, the inoculum suspensions were made by dissolving each isolate in a sterile saline solution. Under the CLSI guideline, the transmittance rate of these suspensions was set to be 73–75% at the wavelength of 540 nm using a spectrophotometer. Then the yeast suspensions were diluted 1:1000 in RPMI 1640 medium, containing 3-N-morpholinepropanesulfonic acid (MOPS) (Bio basic, Canada) as a buffer and chloramphenicol as an antibiotic to inhibit bacterial growth. After dilution, the final concentration of each inoculum suspension reached 1–3 × 103 CFU/ml. First, all 96-well plates should be filled with 0.1 ml of RPMI 1640 medium; then the indicated concentrations of both alcoholic and aqueous extracts of C. annum along with the yeast suspensions were added to them. These plates were incubated at 35 °C for 2 days. The final concentrations of both aqueous and alcoholic extracts were 1, 2, 4, 8, 16, 32, 64, 128, 256, and 512 µg/ml. Eventually, the minimum inhibitory concentration (MIC) ranges were evaluated visually as the lowest concentration of alcoholic and aqueous extracts, which inhibited at least 80% of the fungal growth in comparison with the positive control, that are included only RPMI and fungal suspension. Moreover, although pungency of pepper extracts was different, pungency did not show a significance efficacy against Candida isolates. Figure 1 show the summarized procedures performed during this study.
Based on the results of this study, none of the compounds, aqueous and alcoholic extracts showed significant fungal growth inhibition, when compared to the positive control. However, among the different variants of C. annum, C. annum var. Cerasiforme was able to reduce the growth rate of Candida species better than other variants used in the study. Although fungal growth was seen in all wells, all three extracts of C. annum showed better results against C. albicans isolates. As Tables 1 and 2 summarized and provide the data analysis, neither aqueous nor alcoholic extracts of C. annum showed any significant MIC (≥ 512 µg/ml) values among clinical isolates and reference strains of Candida species. Moreover, although pungency of pepper extracts were different, these differences did not show significant role against Candida isolates.
The incidence of all clinical forms of candidiasis is increasing rapidly, especially among immunocompromised patients [21, 22]. Moreover, the emergence of resistance to conventional antifungal agents urges scientists to expand novel therapeutics against infections caused by Candida species. As an example, studies show that fluconazole resistance can be caused by cellular changes induced by stress responses or upregulation of drug transporters . Furthermore, multidrug-resistant species like C. glabrata and C. auris are becoming more prevalent . Historically, natural products have provided key start-point compounds for therapeutic use. Most of the antimicrobial agents have been traditionally obtained from medicinal plants. In-vitro and in vivo antimicrobial activities of herbal extracts and their products such as seeds or fruits have been studied in different regions of the world, which have reported the presence of a wide variety of substances that can restrict the growth of many fungal agents. Based on various studies, some plants or herbal extracts are exhibited to be effective in preventing or curing infectious diseases. Hence, this study has further evaluated the antifungal activity of Capsicum annum extracts against clinical and reference isolates of Candida species.
Antifungal activities of herbal extracts and medicinal plants were studied overtime against a wide range of fungal agents, such as the antifungal activity of black pepper (Piper nigrum leaves) described against Fusarium oxysporum and Aspergillus niger . The acetone extract of Piper nigrum leaves showed an effective impact on the mycelial growth of F. graminearum, Penicillium viridcatum, and A. ochraceus . In 2014, a study reported the antifungal effects of Pelargonium zonale stalks against C. albicans. The results of this study were based on microscopic analysis, which indicated morphological changes like cell wall damage and deformations of the cell surface . Another research studied the effects of Astronium urundeuva leaves and demonstrated the antifungal activity by using its free extract and microemulsion against C. glabrata and C. albicans . Based on a study conducted by Prabhakar et al., alcoholic extracts of Syzygium jambolanum, Cassia siamea, Caulerpa scalpelliformis, and Sargassum wightii showed significant antifungal activity against Candida species isolated from oral lesions . In another study in Saudi Arabia, researchers evaluated the antifungal activity of a traditional plant called Myrtus communis against Candida species; the results showed that its root and leaf extracts had acceptable antifungal activity against C. glabrata through damaging the cell membrane . In 2018, Jameel et al. studied the antifungal activities of methanolic, hexane, and aqueous extracts of Capparis deciduas against C. albicans and concluded that the methanolic extract had a more significant inhibitory effect against the fungal species used in the study . Wenji et al. researched to determine about the antifungal activity of Peppermint (Mentha piperita leaves), which showed a high inhibitory activity of Mint leaf extracts against C. albicans . In 2015, Aloe vera extracts were assessed and showed considerable antifungal activity against C. albicans . Studies by Sytykiewicz et al. concluded that methanolic extracts of walnut leaves have the highest antifungal activity against C. albicans, while its ethyl acetate and hydrolyzed methanolic extracts exhibit lower inhibitory effects against C. albicans’ growth rate . On the other hand, the features of sweet pepper (C. annum leaves) have shown that it is best known as a source of Vitamins C and E . Currently, in India, America, and China, C. annum is being used as a treatment for arthritis, rheumatism, dog/snake bites, and flesh wounds . C. annum has different genotypes and seasonal breeding and grows in different shapes, sizes, and colors, which can affect its antifungal activity . Many studies were conducted and showed that C. annum has potential antibacterial and antioxidant activities. Moreover, it can positively affect human breast, prostate, and cervical tumors . Although in some studies the effectiveness of Capsicum extracts was not uniform, there is strong evidence about the antibacterial effects of these extracts against S. aureus, S. typhimurium, and V. cholerae . According to a study in 2012, C. annuum var. Antillais and C. Frutescens var. Soudanese showed great antibacterial effects against V. cholerae . As of today, there is no conclusive research about the antifungal effects of C. annuum, therefore this study was conducted as an attempt to discover whether C. annuum, as an antifungal agent, has any impact on Candida isolates or not. Since some plant extracts have specific active substances that attack different structures of fungal agents, in this case, these active substances in pepper are probably weak or ineffective against wall structures, cytoplasmic membrane and proteins. Therefore although the current study yielded no significant results, more studies should be done due to the lack of knowledge in this field.
The results of the present study showed that none of the compound, aqueous and alcoholic extracts of C. annuum had any significant inhibitory effects against clinical and reference strains of Candida. Although the pungency of pepper extracts were different, these differences did not show a significant role against Candida isolates. The present study has some limitations, including the insufficient number of various species of Candida. Additionally, a small size population of clinical isolates was not included. Thus, further investigations are required to determine whether C. annuum or its active components, such as capsaicin, capsaicinoids, and carotenoids, have any other antifungal activity against Candida spp. or other fungal pathogens.
Based on the fact that there were no comprehensive antifungal studies on C. annum extracts, this study evaluated the effects of both aqueous and alcoholic extracts of this plant against various Candida species. Moreover, due to the emergence of antifungal drug resistance can be a crucial issue.
Availability of data and materials
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
- CLSI :
Clinical and laboratory standards institute
Esmailzadeh A, Zarrinfar H, Fata A, Sen T. High prevalence of candiduria due to non-albicans Candida species among diabetic patients: a matter of concern? J Clin Lab Anal. 2018;32(4):e22343.
Kauffman CA, Pappas PG, Sobel JD, Dismukes WE. Essentials of clinical mycology. Massachusetts: Springer; 2011.
Zarrinfar H, Kaboli S, Dolatabadi S, Mohammadi R. Rapid detection of Candida species in bronchoalveolar lavage fluid from patients with pulmonary symptoms. Braz J Microbiol. 2016;47:172–6.
Odds F. Ecology of Candida and Epidemiology of Candidadosis. In: Candida and candidosis. 1988. p. 68–92.
Arastehfar A, Daneshnia F, Najafzadeh MJ, Hagen F, Mahmoudi S, Salehi M, Zarrinfar H, Namvar Z, Zareshahrabadi Z, Khodavaisy S. Evaluation of molecular epidemiology, clinical characteristics, antifungal susceptibility profiles, and molecular mechanisms of antifungal resistance of Iranian Candida parapsilosis species complex blood isolates. Front Cell Infect Microbiol. 2020;10:206.
Katiraee F, Eidi S, Bahonar A, Zarrinfar H, Khosravi A. Comparision of MICs of some Iranian herbal essences against azole resistance and azole susceptible of Candida Albicans. J Med Plants. 2008;7(27):37–44.
Kazemi M, Akbari A, Zarrinfar H, Soleimanpour S, Sabouri Z, Khatami M, Darroudi M. Evaluation of antifungal and photocatalytic activities of gelatin-stabilized selenium oxide nanoparticles. J Inorg Organomet Polym Mater. 2020;30(8):3036–44.
Gupta SC, Patchva S, Koh W, Aggarwal BB. Discovery of curcumin, a component of golden spice, and its miraculous biological activities. Clin Exp Pharmacol Physiol. 2012;39(3):283–99.
Pulido-Moran M, Moreno-Fernandez J, Ramirez-Tortosa C, Ramirez-Tortosa M. Curcumin and health. Molecules. 2016;21(3):264.
Azari B, Zahmatkesh Moghadam S, Zarrinfar H, Tasbandi A, Jamialahmadi T, Sahebkar A. Antifungal activity of curcuminoids and difluorinated curcumin against clinical isolates of Candida species. In: Natural Products and Human Diseases. Switzerland: Springer; 2021. p. 123–9.
Mahmood K, Zia KM, Zuber M, Salman M, Anjum MN. Recent developments in curcumin and curcumin based polymeric materials for biomedical applications: a review. Int J Biol Macromol. 2015;81:877–90.
Baldemir A, Köngül E, Ildiz N, İlgün S. Investigations on Capsicum annuum L. samples purchased from Kayseri province of Turkey. Turk J Pharm Sci. 2015;12(3):1–15.
Olatunji TL, Afolayan AJ. The suitability of chili pepper (Capsicum annuum L.) for alleviating human micronutrient dietary deficiencies: a review. Food Sci Nutr. 2018;6(8):2239–51.
Maracahipes ÁC, Taveira GB, Sousa-Machado LY, Machado OLT, Rodrigues R, Carvalho AO, Gomes VM. Characterization and antifungal activity of a plant peptide expressed in the interaction between Capsicum annuum fruits and the anthracnose fungus. Biosci Rep. 2019;39(12):BSR20192803.
Niderman T, Genetet I, Bruyère T, Gees R, Stintzi A, Legrand M, Fritig B, Mösinger E. Pathogenesis-related PR-1 proteins are antifungal. Isolation and characterization of three 14-kilodalton proteins of tomato and of a basic PR-1 of tobacco with inhibitory activity against Phytophthora infestans. Plant Physiol. 1995;108(1):17–27.
Koffi-Nevry R, Kouassi KC, Nanga ZY, Koussémon M, Loukou GY. Antibacterial activity of two bell pepper extracts: Capsicum annuum L. and Capsicum frutescens. Int J Food Prop. 2012;15(5):961–71.
Raybaudi-Massilia R, Suárez AI, Arvelo F, Zambrano A, Sojo F, Calderón-Gabaldón MI, et al. Cytotoxic, antioxidant and antimicrobial properties of red sweet pepper (Capsicum annuum L. Var. Llanerón) extracts: in vitro study. Int J Food Stud. 2017;6(2):222–31.
Kashefi E, Seyedi S, Zarrinfar H, Fata A, Mehrad-Majd H, Najafzadeh M. Molecular identification of Candida species in bronchoalveolar lavage specimens of hospitalized children with respiratory disorders. J Babol Univ Medical Sci. 2021;23:331–6.
Rakhshandeh H, Heidari A, Pourbagher-Shahri AM, Rashidi R, Forouzanfar F. Hypnotic effect of A. absinthium hydroalcoholic extract in pentobarbital-treated mice. Neurol Res Int. 2021;2021:5521019.
Rashidi R, Ghorbani A, Rakhshandeh H, Mousavi SH. Protective effect of Artemisia absinthium on 6-hydroxydopamine-induced toxicity in SH-SY5Y cell line. Avicenna J Phytomed. 2021;11(3):238.
Barmar P, Zarrinfar H, Jarahi L, Fata A. Comparison of Candida species in patients with Candida vulvovaginitis in Torbat-e Jam and its relationship with diabetes. Iran J Obstet Gynecol Infertil. 2021;23(11):60–7.
Medina N, Soto-Debrán J, Seidel D, Akyar I, Badali H, Barac A, et al. MixInYeast: a multicenter study on mixed yeast infections. J Fungi. 2021;7:13.
Sardari A, Zarrinfar H, Mohammadi R. Detection of ERG11 point mutations in Iranian fluconazole-resistant Candida albicans isolates. Curr Med Mycol. 2019;5(1):7.
Prasad CS, Shukla R, Kumar A, Dubey N. In vitro and in vivo antifungal activity of essential oils of Cymbopogon martini and Chenopodium ambrosioides and their synergism against dermatophytes. Mycoses. 2010;53(2):123–9.
Yohannes A, Eyalarasan K, Eyob L, Yemane A. Antibacterial and antifungal activities of easily grown Eritrean black pepper. Int J Eng Res Technol. 2018;7.
Singh G, Marimuthu P, Catalan C, DeLampasona M. Chemical, antioxidant and antifungal activities of volatile oil of black pepper and its acetone extract. J Sci Food Agric. 2004;84(14):1878–84.
Lewtak K, Fiołka MJ, Szczuka E, Ptaszyńska AA, Kotowicz N, Kołodziej P, Rzymowska J. Analysis of antifungal and anticancer effects of the extract from Pelargonium zonale. Micron. 2014;66:69–79.
Bonifácio BV, Vila TVM, Masiero IF, da Silva PB, Da Silva IC, de Oliveira LÉ, dos Santos Ramos MA, de Souza LP, Vilegas W, Pavan FR. Antifungal activity of a hydroethanolic extract from Astronium urundeuva leaves against Candida albicans and Candida glabrata. Front Microbiol. 2019;10:2642.
Prabhakar K, Kumar LS, Rajendran S, Chandrasekaran M, Bhaskar K, Khan AS. Antifungal activity of plant extracts against Candida species from oral lesions. Indian J Pharm Sci. 2008;70(6):801.
Alyousef AA. Antifungal activity and mechanism of action of different parts of Myrtus communis growing in Saudi Arabia against Candida Spp. J Nanomater. 2021;2021:1–10.
Jameel S, Ahmad S, Akram M, Zainab R, Sharif A. Antifungal activity in the methanolic, aqueous and hexane extracts of Capparis deciduas. Eur J Inflamm. 2018;16:2058739218781701.
Wenji K, Rukmi I, Suprihadi A. In vitro antifungal activity of methanolic and chloroform mint leaves (Mentha piperita L.) extracts against Candida albicans. J Phys: Conference Series. 2019. Conf. Ser. 1217 012136 012136:1–7.
Shireen F, Manipal S, Prabu D. Anti-fungal activity of Aloe vera: In vitro study. SRM J Res Dental Sci. 2015;6(2):92.
Sytykiewicz H, Chrzanowski G, Czerniewicz P, Leszczyński B, Sprawka I, Krzyżanowski R, Matok H. Antifungal activity of Juglans regia (L.) leaf extracts against Candida albicans isolates. Pol J Environ Stud. 2015;24(3):1339–48.
We appreciate the staff of Medical Mycology and Parasitology Laboratory in Ghaem Teaching hospitals affiliated to Mashhad University of Medical Sciences.
This work was financially supported by the Deputy of Research of Mashhad University of Medical Sciences (MUMS) (grant No. 981730).
Ethics approval and consent to participate
This study was approved by the Ethics Committee of Mashhad University of Medical Sciences (MUMS) with ethics committee code of IR.MUMS.MEDICAL.REC.1399.454.
Consent for publication
The authors declare no competing interests.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Moghadam, S., Azari, B., Rashidi, R. et al. Antifungal activity of three different varieties of Capsicum annuum against clinical isolates of Candida species. Trop Dis Travel Med Vaccines 9, 9 (2023). https://doi.org/10.1186/s40794-023-00194-w