The history, stereochemistry, ethnopharmacology and quality assessment of borneol

ETHNOPHARMACOLOGICAL RELEVANCE

Borneol (BO) represents a global trade-driven spreading of ethnic medicine traceable to the classical age, and won its name specific to its original habitat "Borneo". BO shows broad spectral pharmacological effects, such as anti-inflammatory, analgesic, antipyretic, inducing resuscitation, and widely applied in the protection and treatment of cardiovascular and cerebrovascular diseases, used singly or mostly in compound formulae.

AIM OF THE STUDY

Three stereoscopic configuration forms of BO, l-borneol (LB), d-borneol (DB), and dl-borneol (synthetic, SB), are formulated in broad spectral application, yet their diverse pharmacodynamic and pharmacokinetic properties caused by configurations, and accurate assay and quality assessment are often overlooked. A systematic review and analysis of lumped studies and applications is necessary to clarify the relationship between configuration and its original plant, analysis method, activity and side effect BO in order to guarantee the efficacy and safety during their application.

MATERIALS AND METHODS

The public databases including PubMed, Web of Science, Google Scholar, China National Knowledge Infrastructure were referenced to summarize a comprehensive research and application data of BO published up to date.

RESULTS

This review includes following sections: History and current status, Stereochemistry, Ethnopharmacology, and Quality assessment. In the section of history, the changes of the plant origins of the two isomeric forms of natural BO were described respectively, and the methods for synthetic racemate SB were also included. The section of stereochemistry deals with the stereoscopic structures, physical/chemical property, optical rotation of the three forms of BO, as well as the main related substances like isoborneol, obtained in SB via chemical transformation of camphor and turpentine oil. In the section of Ethnopharmacology, pharmacological activities and pharmacokinetics of different forms of BO were discussed. BO is usually used as an "adjuvant", by enhancing the permeability of the blood-brain barrier and intervene the ADME/T pathways of the other ingredients in the same formulation. In the section of quality assessment, the analytical methods, including chromatography, especially GC, and spectroscopy were addressed on the chiral separation of the coexisting enantiomers.

CONCLUSIONS

This overview systematically summarized three forms of BO in terms of history, stereochemistry, ethnopharmacology, and quality assessment, which, hopefully, can provide valuable information and strategy for more reasonable application and development of the globally reputed ethnic medicine borneol with characteristics in stereochemistry.

l-Borneol Exerted the Neuroprotective Effect by Promoting Angiogenesis Coupled With Neurogenesis via Ang1-VEGF-BDNF Pathway

At present, Stroke is still one of the leading causes of population death worldwide and leads to disability. Traditional Chinese medicine plays an important role in the prevention or treatment of stroke. l-borneol, a traditional Chinese medicine, has been used in China to treat stroke for thousands of years. However, its mechanism of action is unclear. After cerebral ischemia, promoting angiogenesis after cerebral ischemia and providing nutrition for the infarct area is an important strategy to improve the damage in the ischemic area, but it is also essential to promote neurogenesis and replenish new neurons. Here, our research shows that l-borneol can significantly improve the neurological deficits of pMCAO model rats, reduce cerebral infarction, and improve the pathological damage of cerebral ischemia. and significantly increase serum level of Ang-1 and VEGF, and significantly decrease level of ACE and Tie2 to promote angiogenesis. PCR and WB showed the same results. Immunohistochemistry also showed that l-borneol can increase the number of CD34 positive cells, further verifying that l-borneol can play a neuroprotective effect by promoting angiogenesis after cerebral ischemia injury. In addition, l-borneol can significantly promote the expression level of VEGF, BDNF and inhibit the expression levels of TGF-β1 and MMP9 to promote neurogenesis. The above suggests that l-borneol can promote angiogenesis coupled neurogenesis by regulating Ang1-VEGF-BDNF to play a neuroprotective effect. Molecular docking also shows that l-borneol has a very high binding rate with the above target, which further confirmed the target of l-borneol to improve cerebral ischemic injury. These results provide strong evidence for the treatment of cerebral ischemia with l-borneol and provide reference for future research.

NIR Rapid Assessments of Blumea balsamifera (Ai-na-xiang) in China

Blumea balsamifera (Ai-na-xiang) is used as an important plant source of natural borneol, which is widely used in the pharmaceutical industry. The aim of this study was to establish the methods based on near infrared (NIR) spectroscopy for determining the geographical origin of B. balsamifera, as well as developing a method for the quantitative rapid analysis of the active pharmaceutical ingredients (APIs). A total of 109 samples were collected from China in 2013 and arbitrarily divided into calibration and prediction sets using the Kennard–Stone algorithm. The l-borneol and total flavone contents of the samples were measured by gas chromatography and ultraviolet-visible spectroscopy, respectively. The NIR spectra were acquired using an integrating sphere and a partial least squares (PLS) model was built using the optimum wavelength regions, which were selected using a synergy interval partial least-squares (SiPLS) algorithm. The root mean square errors of prediction of the l-borneol and total flavone models were 0.0779 and 2.2694 mg/g, with R² of 0.9069 and 0.8013, respectively. A discriminant model to determine the geographical origin of B. balsamifera (Guizhou and Hainan) was also established using a partial least squares discriminant analysis method with an optimum pretreatment method. The prediction accuracy rate of the model was 100%. NIR spectroscopy can be used as a reliable and environmentally friendly method to determine the API and the origin of different B. balsamifera samples.