Chemical profiling and quality evaluation of raw and vinegar‐processing frankincense by multiple UPLC‐MS/MS techniques

Abstract Introduction Frankincense is used for analgesic, tumor‐suppressive, and anti‐inflammatory treatments in Traditional Chinese Medicine but poses toxicological concerns. Vinegar processing is a common technique used to reduce the toxicity of frankincense. Objective This study aimed to investigate the chemical composition and quality evaluation of raw and vinegar‐processing frankincense by multiple UPLC‐MS/MS techniques. Additionally, we purposed refining the vinegar processing technique and identifying potentially harmful ingredients in the raw frankincense. Methodology Sub‐chronic oral toxicity studies were conducted on raw and vinegar‐processing frankincense in rats. The composition of frankincense was identified by UPLC‐Q‐TOF‐MS/MS. Chemometrics were used to differentiate between raw and vinegar‐processing frankincense. Potential chemical markers were identified by selecting differential components, which were further exactly determined by UPLC‐QQQ‐MS/MS. Moreover, the viability of the HepG2 cells of those components with reduced contents after vinegar processing was assessed. Results The toxicity of raw frankincense is attenuated by vinegar processing, among which vinegar‐processing frankincense (R40) (herb weight: rice vinegar weight = 40:1) exhibited the lowest toxicity. A total of 83 components were identified from frankincense, including 40 triterpenoids, 37 diterpenoids, and 6 other types. The contents of six components decreased after vinegar‐processing, with the lowest levels in R40. Three components, specifically 3α‐acetoxy‐11‐keto‐β‐boswellic acid (AKBA), 3α‐acetoxy‐α‐boswellic acid (α‐ABA), and 3α‐acetoxy‐β‐boswellic acid (β‐ABA), inhibited the viability of HepG2 cells. The processing of frankincense with vinegar at a ratio of 40:1 could be an effective method of reducing the toxicity in raw frankincense. Conclusion Our research improves understanding of the toxic substance basis and facilitates future assessments of frankincense quality.