Capsaicin and neurokinin A-induced bronchoconstriction in the anaesthetised guinea-pig: evidence for a direct action of menthol on isolated bronchial smooth muscle

1. For many years menthol has been used in the treatment of respiratory disorders although, a bronchodilator effect of menthol has yet to be described. Using the bronchoconstrictors capsaicin (acting via stimulating the release of neuropeptides from sensory afferents) and neurokinin A (NKA) we have raised airways resistance in the guinea-pig (GP) and studied the effect of menthol on both capsaicin and NKA-induced bronchoconstriction in vivo. In vitro the effect of menthol on acetylcholine (ACh) and KCl precontracted GP bronchi was also studied.
2. GP (n=13) were anaesthetized (urethane 1.5 g kg⁻¹, i.p.) and a bolus injection of capsaicin (7.5 μg ml⁻¹, i.v.) or infusion of NKA (1 μg min⁻¹, i.v.) was given either in the presence of air (0.81 min⁻¹) or air impregnated with menthol vapour (7.5 μg l⁻¹) freely breathed from a tracheal cannula via a T-piece. Airways resistance (R_aw) and ventilation were measured throughout. Bronchi of mean internal diameter (1029+73.6 μm; n=24) were removed from GP (n=16) and mounted in the Cambustion myograph. Bronchial rings were maximally precontracted with 80 mM KC1 or 2 mM ACh. Relaxation due to a cumulative dose of menthol (1–3000 μM) was measured.
3. Menthol produced a significant (P<0.05) 51.3% reversal of the capsaicin-induced increase in R_aw, and also inhibited the significant (P<0.05) reduction in minute ventilation (V_e) associated with the capsaicin-induced increased in R_aw. Menthol also caused a significant (P<0.05) 41% reversal of the NKA-induced increase in R_aw. The NKA-induced decrease in V_e was again significantly (P<0.05) reversed with menthol inhalation. Menthol caused a significant (P<0.001) dose-dependent relaxation of KCl and ACh precontracted bronchi.
4. We have shown that menthol attenuates both capsaicin and NKA-induced bronchoconstriction in vivo and relaxes KCl and ACh preconstricted bronchi in vitro. Menthol inhibition of NKA and capsaicin-induced bronchoconstriction could be, in part, explained by a direct action of menthol on bronchial smooth muscle.

     

气相色谱法测定止痒洗剂中苯酚和薄荷脑的含量

目的建立气相色谱(GC)法测定止痒洗剂中苯酚和薄荷脑的含量方法,为止痒洗剂质量控制提供有效的分析手段。方法色谱柱:以HP-5(95%二甲基-5%二苯基聚硅氧烷,0.25 mm×30.0 m)毛细管柱为色谱柱;柱温为60℃;以8℃/min速率升温至160℃,保温10 min,进样口温度180℃,FID检测器,检测器温度300℃。空气流速为300 ml/min,分流比为20∶1。进样量1μl。结果苯酚和薄荷脑的线性范围分别是0.45～9 mg/ml和0.25～5 mg/ml,回归方程分别是A=1.476 9C-0.109 9(r=0.999 9)和A=1.393 7C-0.095 9(r=0.999 9)。苯酚和薄荷脑的平均回收率分别为100.6%(RSD=0.73%)和100.8%[相对标准偏差(RSD)=0.76%]。结论该方法简单,结果准确可靠,可用于止痒洗剂中苯酚和薄荷脑的含量测定。     

气相色谱法测定强力枇杷露中薄荷脑、磷酸可待因、吗啡、盐酸罂粟碱的含量

目的：建立气相色谱法同时测定强力枇杷露中薄荷脑、磷酸可待因、吗啡、盐酸罂粟碱四种成分含量的方法。方法：试样用乙酸乙酯振摇提取,色谱柱为100%二甲基聚硅氧烷固定液的毛细管柱,柱温从100℃程序升温至270℃,保持20 min,检测器为 FID。结果：薄荷脑、磷酸可待因、吗啡、盐酸罂粟碱在各自测定范围内有良好线性关系,各成分平均回收率（n=6）在96.76%~113.34%,RSD<6.0%。结论：本方法准确可靠,重现性好,可有效地控制强力枇杷露的质量。     

薄荷药材的提取与含量测定

目的探讨建立薄荷药材的提取和含量测定方法。方法以薄荷脑为指标成分,采用DM—FFAP弹性石英毛细管柱,初始柱温为120℃,以2℃／min升温至140＇C,然后以15℃／min升温至220℃,保持5min。比较索氏提取、加热回流、超声提取法的差异,并优选最佳提取方法。结果最佳提取工艺：加10倍量无水乙醇溶液85℃回流提取1h。薄荷脑在34．034～343．04μg／ml浓度范围内线性关系良好,平均回收率为99．00％,RSD=1．87％（n=6）。结论本文所建立的提取和含量测定方法快速简便、结果可靠,可为薄荷药材质量控制提供科学依据。     

毛细管气相色谱法测定复方薄荷脑滴鼻液中薄荷脑和樟脑的含量

目的建立毛细管气相色谱法测定复方薄荷脑滴鼻液中薄荷脑和樟脑的含量。方法采用毛细管气相色谱法,色谱柱为HP-INNOWAX(0.53mm×30m,1μm)弹性石英毛细管色谱柱,采用程序升温法,检测器温度为250℃,载气为N2,流速为5ml/min,进样口温度为200℃。结果薄荷脑和樟脑的回归方程分别为:Y=1.2286X-0.002214(r=0.9999),Y=1.2504X-0.002929(r=0.9999);线性范围分别为16.72~117.04μg·ml-1,17.52~122.64μg·ml-1,回收率分别为:101.5%,101.1%,RSD分别为0.40%、0.66%(n=10)。结论本法简便,快速,准确,可靠,适用于复方薄荷脑滴鼻液的质量控制。     

高效液相色谱法测定炉甘石薄荷脑洗剂中苯酚的含量

目的测定炉甘石薄荷脑洗荆中苯酚的含量.方法采用HPLC法以Kromasil C18色谱柱(4.6 mm x250mm,5μm),流动相为甲醇-水(6535),检测波长270 nm.结果苯酚的浓度在40～180 mg·L-1范围内线性关系良好(r=0.999 8),平均回收率为100.1%,方法精密度ILSD=0.45%( n=5).结论该法简便、快速、准确,可作为炉甘石薄荷脑洗剂中苯酚的含量测定方法.     

GC法测定复方盐酸阿扑吗啡鼻喷剂中薄荷脑的含量

目的：建立新药复方盐酸阿扑吗啡鼻喷剂中薄荷脑（C10H20O）的含量测定方法。方法：采用PEG-20M石英毛细管色谱柱（CBP125M×0．25μm，日本岛津）气相色谱法。检测器：氢火焰离子化检测器（FID）；柱温：程序升温，初始温度80℃，保持2分钟，以每分种10℃的速率升温至180℃；进样口温度：180℃；检测器温度：200℃：载气：氮气；流速：40ml／分钟；分流比：1：50。以正十四烷为内标物，内标法定量。结果：薄荷脑在0．188～2．25mg·ml^-1范围内与峰面积呈良好的线性关系，r=0．99998（n=7）；回收率为98．2％。分析了3批样品，薄荷脑的含量为标示量的99．4％～100．0％。结论：本法专属性强、简便、准确。为该复方制剂中薄荷脑成分提供了切实可行的质控方法。     

毛细管气相色谱法同时测定活络油中7种成分的含量

目的:建立活络油中有效成分α-蒎烯、桉油精、樟脑、薄荷脑、水杨酸甲酯、桂皮醛、丁香酚的气相色谱测定法。方法:色谱条件为DB-1毛细管色谱柱,柱温90℃,保持1 min后,以6℃.min-1升至180℃后,继续以25℃.min-1升至250℃,保持5min,载气为氮气。进样口温度为220℃,检测器温度为260℃,FID检测器,无分流进样。结果:α-蒎烯的线性范围6.94~41.64μg.mL-1,桉油精的线性范围1.00~6.01μg.mL-1,樟脑的线性范围6.86~41.18μg.mL-1,薄荷脑的线性范围24.09~144.55μg.mL-1,水杨酸甲酯的线性范围24.16~144.98μg.mL-1,桂皮醛的线性范围1.03~6.17μg.mL-1,丁香酚的线性范围1.04~6.25μg.mL-1,RSD分别为1.8,1.1,0.9,0.7,1.1,1.7,1.1%。结论:方法简便、准确,可用于活络油的质量控制。     

气相色谱法测定辣椒风湿膏中薄荷脑与冰片的含量

目的建立辣椒风湿膏中薄荷脑与冰片的含量测定方法。方法采用气相色谱法,用水蒸气蒸馏法提取薄荷脑、冰片,以萘作为内标物,使用PEG20M色谱柱,用氢火焰离子检测器检测。结果通过方法学考察,薄荷脑在1.008μg～5.042μg范围内呈良好的线性关系,平均回收率为95.9%(n=5)。冰片在1.008μg～5.040μg范围内呈良好的线性关系,平均回收率为96.0%(n=5)。结论方法简便、准确、重现性好、精密度高。可用于控制辣椒风湿膏的质量。     

气相色谱法法测定苍耳子鼻炎胶囊中薄荷脑和龙脑的报告

目的建立测定苍耳子鼻炎胶囊中薄荷脑和龙脑含量的可靠方法。方法用气相色谱法检测,以聚乙二醇(PEG)-20M为固定相,涂布浓度为10%金属填充柱。结果薄荷脑、龙脑在1.0～10.0μg范围里呈较好的线性关系;薄荷脑和龙脑的回收率为分别为98.78%和98.49%。结论气相色谱法操作简单,结果可靠,重复性好,为苍耳子鼻炎胶囊质量控制提供了新的手段。