Chong Yie Kie, Gan Wei Khang, Tan Joash Ban Lee, Mohd Jaaffar Ahmad Kamil Hj, Baharum Zainal, Yeong Keng Yoon
School of Science, Monash University Malaysia Campus, Bandar Sunway, Malaysia.
Malaysian Cocoa Board, Kota Kinabalu, Malaysia.
J Sci Food Agric. 2025 Sep;105(12):6495-6505. doi: 10.1002/jsfa.14366. Epub 2025 May 13.
Cocoa bean shell (CBS) extracts have emerged as a promising source of antimicrobial compounds. However, the bioactive compounds responsible for their antimicrobial activity have not been studied sufficiently. This study analyzed the antimicrobial properties of 12 extracts from fermented and non-fermented CBS, employing solvent and steam distillation extraction techniques to maximize bioactive diversity. The extracts were assessed against selected bacteria and fungi, including the 'ESKAPE' pathogens.
The CBS solvent and steam distillation extracts (except for ethyl acetate-fermented CBS) were found to exhibit antimicrobial activity against Streptococcus mutans with minimum inhibitory concentrations (MICs) as low as 0.0625 mg mL, whereas both fermented and non-fermented steam distillation CBS extracts were found to be active against Candida albicans with MICs at 1 mg mL. Overall, steam distillation extracts possessed enhanced antimicrobial activity in comparison with solvent extracts of CBS. Fermented CBS extracts were found to possess better antimicrobial activity than non-fermented CBS extracts. Metabolomics analysis identified theobromine (TB) and tetramethylpyrazine (TMP) as molecules that contributed to antimicrobial activity against S. mutans. Results showed that caffeine (CAF), TB and TMP were active against S. mutans and Acinetobacter baumannii, whereas CAF and TB were active against C. albicans. Significant synergistic effects of CAF, TB, and TMP with ciprofloxacin (CIP) were observed against Klebsiella aerogenes.
These findings highlight the significant potential of bioactive compounds present in CBS for use in the development of sustainable antimicrobial agents. These naturally occurring compounds, including CAF, TB, and TMP, exhibited notable antimicrobial properties, which could also be harnessed to enhance the activity of commonly used antibiotics such as ciprofloxacin. Future studies could focus on determining the mode of action of these bioactive molecules. © 2025 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
可可豆壳（CBS）提取物已成为一种有前景的抗菌化合物来源。然而，对其抗菌活性起作用的生物活性化合物尚未得到充分研究。本研究分析了12种发酵和未发酵CBS提取物的抗菌特性，采用溶剂和水蒸气蒸馏提取技术以最大化生物活性多样性。对提取物针对选定的细菌和真菌进行了评估，包括“ESKAPE”病原体。
发现CBS溶剂提取物和水蒸气蒸馏提取物（乙酸乙酯发酵的CBS提取物除外）对变形链球菌具有抗菌活性，最低抑菌浓度（MIC）低至0.0625mg/mL，而发酵和未发酵的水蒸气蒸馏CBS提取物对白色念珠菌均有活性，MIC为1mg/mL。总体而言，与CBS的溶剂提取物相比，水蒸气蒸馏提取物具有更强的抗菌活性。发现发酵的CBS提取物比未发酵的CBS提取物具有更好的抗菌活性。代谢组学分析确定可可碱（TB）和四甲基吡嗪（TMP）是对变形链球菌具有抗菌活性的分子。结果表明，咖啡因（CAF）、TB和TMP对变形链球菌和鲍曼不动杆菌有活性，而CAF和TB对白色念珠菌有活性。观察到CAF、TB和TMP与环丙沙星（CIP）对产气克雷伯菌有显著的协同作用。
这些发现突出了CBS中存在的生物活性化合物在开发可持续抗菌剂方面的巨大潜力。这些天然存在的化合物，包括CAF、TB和TMP，表现出显著的抗菌特性，也可用于增强常用抗生素如环丙沙星的活性。未来的研究可以集中在确定这些生物活性分子的作用方式上。©2025作者。由John Wiley & Sons Ltd代表化学工业协会出版的《食品与农业科学杂志》。
