The number of bees has decreased drastically partly due to bacterial pathogens like Paenibacillus larvae that cause American foulbrood disease. The recent emergence of pathogenic resistant strains makes it more difficult to, successfully, treat infections. Research on alternative antibacterial agents from naturally occurring plants that also have low toxicity levels is critical to address the issue of Paenibacillus larvae in bee colonies. Five compounds were screened with a minimal inhibitory concentration (MIC) test in order to identify a compound with effective antibacterial activity against Paenibacillus larvae. Of the tested compounds, pimaric acid showed the best antibacterial activity with a MIC value of 6.25 µg/ml after 48 hours of incubation on MYPGP media. An agar diffusion test also confirmed the anti- Paenibacillus larvae activity of pimaric acid with an inhibitory zone of 10 to 14 mm. Crystal violet assay results suggested that pimaric acid disrupted the plasma membrane of Paenibacillus larvae, causing the leakage of material with an optical density of 260-nm and 280-nm, which confirmed that the compound induces the rupture of this microorganism. Pimaric acid inhibited the formation of a Paenibacillus larvae biofilm in a dose-dependent manner. An additive effect of pimaric acid with tetracycline and terramycin was shown through a checkerboard assay with a fractional inhibitory concentration (FIC) index value of 0.75. Finally, an MTT assay on insect cells of Trichoplusia ni and normal human skin cells from the HaCaT cell line, showed that pimaric acid is safe for both insect cell and human skin cells at the dosage required to treat Paenibacillus larvae.

蜜蜂的数量已大大减少，部分原因是细菌病原体（如Paenibacillus larvae幼虫）引起了美洲臭虫病。病原抗性菌株的最新出现使得成功治疗感染变得更加困难。对天然植物中具有低毒性水平的替代抗菌剂的研究对于解决蜂群中幼芽孢杆菌的问题至关重要。用最小抑菌浓度（MIC）试验筛选了五种化合物，以鉴定对幼虫Paenibacillus幼虫具有有效抗菌活性的化合物。在被测化合物中，海藻酸在MYPGP培养基上孵育48小时后显示出最佳的抗菌活性，MIC值为6.25 µg / ml。琼脂扩散试验还证实了皮马酸的抗Paenibacillus幼虫活性，其抑制区为10至14 mm。结晶紫测定结果表明，海藻酸破坏了Paenibacillus幼虫的质膜，导致光密度为260nm和280nm的物质泄漏，这证实了该化合物诱导了这种微生物的破裂。棕榈酸可抑制Paenibacillus幼虫的形成生物膜呈剂量依赖性。海马酸与四环素和土霉素的累加作用通过棋盘试验显示，分数抑制浓度（FIC）指数值为0.75。最后，MTC分析针对的是Trichoplusia ni昆虫细胞和来自HaCaT细胞系的正常人皮肤细胞，结果表明，海马酸以治疗Paenibacillus幼虫所需的剂量对昆虫细胞和人皮肤细胞都是安全的。