Fragrance material review on l-borneol

Cardiotoxicity of (-)-borneol, (+)-borneol, and isoborneol in zebrafish embryos is associated with Na+ /K+ -ATPase and Ca2+ -ATPase inhibition

Borneol is an example of traditional Chinese medicine widely used in Asia. There are different isomers of chiral borneol in the market, but its toxicity and effects need further study. In this study, we used zebrafish embryos to examine the effects of exposure to three isomers of borneol [(-)-borneol, (+)-borneol, and isoborneol] on heart development and the association with Na⁺ /K⁺ -ATPase from 4 h post-fertilization (4 hpf). The results showed that the three isomers of borneol increased mortality and decreased hatching rate when the zebrafish embryo developed to 72 hpf. All three isomers of borneol (0.01-1.0 mM) significantly reduced heart rate from 48 to 120 hpf and reduced the expression of genes related to Ca²⁺ -ATPase (cacna1ab and cacna1da) and Na⁺ /K⁺ -ATPase (atp1b2b, atp1a3b, and atp1a2). At the same time, the three isomers of borneol significantly reduced the activities of Ca²⁺ -ATPase and Na⁺ /K⁺ -ATPase at 0.1 to 1.0 mM. (+)-Borneol caused the most significant reduction (p < 0.05), followed by isoborneol and (-)-borneol. Na⁺ /K⁺ -ATPase was mainly expressed in otic vesicles and protonephridium. All three isomers of borneol reduced Na⁺ /K⁺ -ATPase mRNA expression, but isoborneol was the most significant (p < 0.01). Our results indicated that (+)-borneol was the least toxic of the three isomers while the isoborneol showed the most substantial toxic effect, closely related to effects on Na⁺ /K⁺ -ATPase.

A mechanistic investigation about hepatoxic effects of borneol using zebrafish

Except for clinical value, borneol is routinely used in food and cosmetics with seldom safety evaluation. To investigate its hepatoxicity, we exposed 3 dpf (days post fertilization) larval zebrafish to borneol at a gradient of concentrations (200-500 μM) for 3 days. Herein, our results revealed that high doses of borneol (300-500 μM) caused liver size decrease or lateral lobe absence. Borneol also seriously disturbed the hepatic protein metabolism presented with the increased activity of alanine aminotransferase (ALT) and lipid metabolism shown with the increased level of triglycerides (TG) and total cholesterol (TC). The lipid accumulation (oil red staining) was detected as well. Additionally, significant upregulation of genes was detected that related to oxidative stress, lipid anabolism, endoplasmic reticulum stress (ERS), and autophagy. Conversely, the lipid metabolism-related genes were markedly downregulated. Moreover, the changes in the superoxide dismutase activity and the level of glutathione and malondialdehyde raised the likelihood of lipid peroxidation. The outcomes indicated the involvement of oxidative stress, ERS, lipid metabolism, and autophagy in borneol-induced lipid metabolic disorder and hepatic injury. This study will provide a more comprehensive understanding of borneol hepatoxicity and the theoretical basis for the safe use of this compound.

Progress in Borneol Intervention for Ischemic Stroke: A Systematic Review

Background: Borneol is a terpene and bicyclic organic compound that can be extracted from plants or chemically synthesized. As an important component of proprietary Chinese medicine for the treatment of stroke, its neuroprotective effects have been confirmed in many experiments. Unfortunately, there is no systematic review of these studies. This study aimed to systematically examine the neuroprotective effects of borneol in the cascade reaction of experimental ischemic stroke at different periods. Methods: Articles on animal experiments and cell-based research on the actions of borneol against ischemic stroke in the past 20°years were collected from Google Scholar, Web of Science, PubMed, ScienceDirect, China National Knowledge Infrastructure (CNKI), and other biomedical databases. Meta-analysis was performed on key indicators in vivo experiments. After sorting the articles, we focused on the neuroprotective effects and mechanism of action of borneol at different stages of cerebral ischemia. Results: Borneol is effective in the prevention and treatment of nerve injury in ischemic stroke. Its mechanisms of action include improvement of cerebral blood flow, inhibition of neuronal excitotoxicity, blocking of Ca²⁺ overload, and resistance to reactive oxygen species injury in the acute ischemic stage. In the subacute ischemic stage, borneol may antagonize blood-brain barrier injury, intervene in inflammatory reactions, and prevent neuron excessive death. In the late stage, borneol promotes neurogenesis and angiogenesis in the treatment of ischemic stroke. Conclusion: Borneol prevents neuronal injury after cerebral ischemia via multiple action mechanisms, and it can mobilize endogenous nutritional factors to hasten repair and regeneration of brain tissue. Because the neuroprotective effects of borneol are mediated by various therapeutic factors, deficiency caused by a single-target drug is avoided. Besides, borneol promotes other drugs to pass through the blood-brain barrier to exert synergistic therapeutic effects.

Influence of Orally Administered Borneol on the Expression of Hepatic Transporters in Rats

BACKGROUND AND OBJECTIVE

Borneol, a traditional Chinese medicine (TCM), is often orally co-administered with other TCM and chemical drugs, but the drug-drug interactions between borneol and the other compounds remains unclear. This work investigates the effect of orally administered borneol on the transcription and expression of hepatic uptake transporters (Ntcp, Oatp2b1, Oatp1a1, Oatp1a4, Oct1, Oct2, Octn2 and Oat2) and efflux transporters (Mdrla, Mrp2, Mrp4 and Mrp5) in rats, aiming to obtain essential information to guide its clinical applications.

METHODS

Rats were administered borneol (33, 100 and 300 mg/kg/day, respectively) and vehicle (control) orally via intragastric gavage for 7 consecutive days. The mRNA levels of rat hepatic uptake transporters (Ntcp, Oatp2b1, Oatp1a1, Oatp1a4, Oct1, Oct2, Octn2 and Oat2) and efflux transporters (Mdrla, Mrp2, Mrp4 and Mrp5) were determined using real-time quantitative PCR, while the hepatic Ntcp, Mdrla, Mrp2, Mrp4 and Mrp5 proteins were quantified using western blotting.

RESULTS

The oral administration of borneol led to dose-dependent inhibition of mRNA and protein expression of Mrp4 and Mdr1a, dose-independent inhibition of mRNA and protein expression of Mrp2, and inverse dose-dependent inhibition of mRNA and protein expression of Ntcp. No significant effects were observed for mRNA expression of the other transporters tested following borneol administration.

CONCLUSIONS

Oral administration of borneol may affect the metabolism of substances that are involved in bile acid enterohepatic circulation and substrates of Ntcp, Mdrla, Mrp2 and Mrp4 transporters.

The Role and Mechanism of Borneol to Open the Blood-Brain Barrier

Background: The blood-brain barrier (BBB) is the greatest challenge in the treatment of intracranial malignant tumors. Objective: The aim of this study is to determine the role of borneol in opening the BBB and elucidate the underlying mechanisms. Materials and Methods: Twenty Sprague-Dawley (SD) rats were randomized into borneol group intragastrically administered with 10% borneol corn oil (2 mL/kg) and control group. After 30 minutes, 2% Evans blue (4 mL/kg) was injected. Thirty minutes later, brain tissue was analyzed using the Evans blue standard curve. Another 40 SD rats were randomized into high-, medium-, and low-dose borneol groups and a control group. Each rat in the experimental groups was intragastrically administered with 10% borneol corn oil (2 mL/kg, 1.25 mL/kg, and 0.5 mL/kg, respectively). The control group was injected with corn oil of 1.25 mL/kg. After 30 minutes, the rats were killed, and the brain tissues were collected. The expression of occludin, occludens-1, nitric oxide synthase, P-glycoprotein, and intercellular cell adhesion molecule-1 (ICAM-1) was detected by immunohistochemy. Results: The concentration of Evans blue in the borneol group was higher than in the control group (P < .05). The mean density of ICAM-1 expression was higher in the experimental group than in the control group (P < .05). In contrast, significant differences of positive area and total density of ICAM-1 were shown only between the high-dose group and the control group (P < .05). Conclusion: Borneol can open the BBB, which might be related with the increased expression of ICAM-1.

Progress and perspectives on targeting nanoparticles for brain drug delivery

Due to the ability of the blood-brain barrier (BBB) to prevent the entry of drugs into the brain, it is a challenge to treat central nervous system disorders pharmacologically. The development of nanotechnology provides potential to overcome this problem. In this review, the barriers to brain-targeted drug delivery are reviewed, including the BBB, blood-brain tumor barrier (BBTB), and nose-to-brain barrier. Delivery strategies are focused on overcoming the BBB, directly targeting diseased cells in the brain, and dual-targeted delivery. The major concerns and perspectives on constructing brain-targeted delivery systems are discussed.

External application of the volatile oil from Blumea balsamifera may be safe for liver--a study on its chemical composition and hepatotoxicity

Ainaxiang (Blumea balsamifera), also known as Sambong, is an important ancient medicinal herb in Southeast Asia. It is rich in volatile oil, and still widely used nowadays for skin wound healing and treatment of sore throats. We analyzed the volatile oil from Blumea balsamifera (BB oil) by gas chromatography-mass spectrometry (GC-MS). Forty one components, including l-borneol, were identified. Next, the damaging effects of BB oil diluted with olive oil on liver at different concentrations (100%, 50%, 20%), were evaluated, using both normal and wounded skin. Plasma ALT, AST, ALP and TBili were assessed, along with liver histopathology. The results showed that serum levels of liver toxicity markers in the high concentration groups (100% w/v) increased compared with control groups, whereas no significant changes was observed in histopathology of liver samples. In the wound groups, treatment with BB oil resulted in a decrease in serum toxicity index, compared with normal animal groups. This study confirms the safety of short term BB oil consumption, though high BB oil doses may lead to mild liver injury and this response might be weakened in the case of cutaneous wounds. These results are expected to be helpful for guiding appropriate therapeutic use of BB oil.