Management of periorbital hyperpigmentation: An overview of nature‐based agents and alternative approaches

Periorbital hyperpigmentation (POH) is a common dermatological condition that presents as dark periorbital area beneath the lower eyelids, and it is commonly found in females belonging to the age group of 16 to 45 years. The data presented in this review include studies conducted on patients with a clinical/histological diagnosis of POH or melasma. Many diverse topical depigmenting agents comprising an array of naturally obtained actives such as arabinoxylans, α‐arbutin, asiaticoside, azelaic acid, beta‐carotene, boswellic acid, caffeine, chrysin, curcumin, cyanidin‐3‐glucoside, d ‐glucoronic acid, dihydrochalcone, dipalmitoyl‐hydroxyprolene, fucoxanthin, genistein, glabridin, b‐glucogallin, hyaluronic acid, lactic acid, lycopene, niacinamide, pycnogenol, retinol, salidroside, and xymenynic acid demonstrated significant benefits in the management of POH. An exhaustive literature search revealed that other techniques such as blepharoplasty, carboxytherapy, calcium hydroxylapatite fillers, tear trough implant, Q‐switched ruby laser, medicated tattoo, fat transfer, micro‐needling, chemical peels, nitrogen plasma skin regeneration, intense pulsed light, and radiofrequency have been evaluated and reported to be beneficial in the treatment of POH. The use of topical depigmenting agents is the most widely reported method in the clinical management of POH. Of these, α‐arbutin, caffeine, cyanidin‐3‐glucoside, and dihydrochalcone are reported to exhibit significant benefits. Combination products containing a blend of actives are reported to be better than single active containing products. This review aims to provide a comprehensive perspective on the role of several topical actives in the modulation of melanin and tyrosinase biosynthesis pathway involved in the complex pathophysiology of POH. It also presents the advantages of combination products and other alternative therapies used in the management of POH.     

Taste responses to neohesperidin dihydrochalcone in rats and baboon monkeys

Preference-aversion behavior to solutions containing neohesperidin dihydrochalcone (NHDHC) was studied rats and baboon monkeys. Electrophysiological responses evoked by application of NHDHC solutions to taste receptors innervated by the chorda tympani and the glossopharyngeal nerves were also measured. As a group, rats were indifferent to solutions containing up to 1.2×10^?3 M NHDHC in short and long-term preference tests. A solution containing the very high concentration of 8.2×10^?3 M NHDHC was consumed less than water by all rats. The aversive behavior of rats to the 8.2×10^?3 M NHDHC solution appeared to be due to taste quality rather than olfaction. When percent preferences were calculated on an individual basis for the long-term preference tests, 59% of the rats were indifferent to solutions containing up to 1.2×10^?3 M NHDHC, 33% of the animals found this solution aversive and less than 8% showed preference. Behavioral responses to a solution of 3.4×10^?4 M aspartame also varied considerably among rats. The electrophysiological data were in line with the behavioral responses suggesting weak taste responses for NHDHC in rats. More pronounced responses observed in the glossopharyngeal nerve as compared to the chorda tympani. Baboon monkeys showed a strong preference for solutions containing 1.6×10^?5 M–1.6×10^?3 M NHDHC. A solution of 1.6×10^?2 M was consumed to a lesser extent than water. It is concluded that baboon monkeys present a better experimental model than rats for investigating the sweetness of NHDHC.     

New dihydrochalcone glycosides from Lithocarpus litseifolius and the phenomenon of C–H→C–D exchange observed in NMR spectra of phenolic components

Two new dihydrochalcone glycosides named 6″-O-acetyltrilobatin (1) and 3″-O-acetylphloridzin (2) as well as four known compounds were isolated from the leaves of Lithocarpus litseifolius (Hance) Chun (family Fagaceae). Their structures were elucidated on the basis of spectroscopic analyses. The phenomena of C–H → C–D exchange were observed in NMR spectra of the isolated phenolic components when measured in deuterated methanol.     

Application of a liquid chromatography–tandem mass spectrometry method to the pharmacokinetics,bioavailability and tissue distribution of neohesperidin dihydrochalcone in rats

Abstract

1.?This study was aimed at developing a high sensitive and selective liquid chromatography–tandem mass spectrometry method to quantify neohesperidin dihydrochalcone (NHDC) in rat plasma and tissues for pharmacokinetic, bioavailability and tissue distribution studies.

2.?Biological samples were processed with one-step protein precipitation. Rutin was chosen as the internal standard (IS). Chromatographical separation was achieved on an SB-C₁₈ (2.1?mm×?150?mm, 5?μm) column with acetonitrile--0.1% formic acid in water as the mobile phase with gradient elution. Electrospray ionization (ESI) source was applied and operated in negative ion mode; selected ion monitoring mode was used for quantification using target fragment ions m/z 611.4 for NHDC and m/z 609.1 for IS.

3.?Calibration plots were linear over the range of 10–3000?ng/mL for NHDC. Lower limit of quantification (LLOQ) for NHDC was 10?ng/mL. Mean recovery of NHDC from plasma and tissues was better than 80.3%. Coefficient of variation of intra-day and inter-day precision were both less than 15%. The bioavailability of NHDC was 21.8%.

4.?In conclusion, a sensitive, simple and specific LC-ESI-MS method for the determination of NHDC in rat biological samples was developed. This developed method is successfully used in the pharmacokinetic and tissue distribution study of NHDC in rats.     

Synthesis of deuterated dihydrochalcones

The dihydrochalcones phloretin and phloridzin are major phenolic constituents of apple fruit. Phloretin‐d₄, deuterated at both the α and β positions, was prepared by hydrogenolysis of naringenin and by deuterium exchange from unlabelled phloretin using Pd/C and sodium formate with methanol‐d₁ as the source of deuterium. Deuterated derivatives of the glycosides, phloridzin and naringin dihydrochalcone, were similarly prepared. Copyright © 2006 John Wiley & Sons, Ltd.     

活细胞固相色谱法联合高分辨质谱快速筛选龙血竭中镇痛活性成分

目的采用活细胞固相色谱法及高分辨液质联用技术快速筛选鉴定龙血竭中潜在的镇痛活性成分。方法首先采用HPLC-DAD-TOF-MS法对龙血竭药材中的主要化学成分信息进行表征,进一步选择以疼痛相关的离子通道受体表达丰富的小鼠背根神经元细胞为靶细胞,先使龙血竭提取液中的活性成分与靶细胞特异性结合,应用液质联用技术快速鉴定与细胞靶向亲和的化学成分。结果从龙血竭药材中鉴定出21个具有不同结构类型的主要成分,采用活细胞固相色谱法共筛选出10种能与背根神经元细胞亲和的潜在活性成分,包括二苯乙烯类2个、高异黄酮2个、高异黄烷1个、二氢查耳酮2个、黄酮寡聚体3个等。结论应用活细胞固相色谱法与高分辨质谱联用技术可快速筛选辨识龙血竭中活性成分,为龙血竭镇痛等活性成分的进一步研究奠定基础,也可为中药药效物质研究提供有益的方法学参考。     

HPLC测定龙血竭胶囊中二氢查耳酮（龙血素A）的含量

目的：建立HPLC法测定龙血竭胶囊中龙血素A的含量。方法：以C18反相键合硅胶为固定相,1％冰醋酸－甲醇（34：66）为流动相,检测波长为280nm,用外标法定量。结果：龙血素A在0．11－4．39μg范围有良好线性关系,r=0.9998,方法回收率为98．28％,RSD为1．97％。结论：本方法是测定龙血竭胶囊中龙血素A含量的可靠、简便的定量方法。     

新橙皮苷二氢查尔酮对流感病毒诱导小鼠肺气血屏障损伤的保护作用

目的 探讨新橙皮苷二氢查尔酮（NHDC）对流感病毒诱导小鼠肺气血屏障损伤的保护作用.方法 建立流感病毒感染小鼠肺炎模型,给予NHDC灌胃治疗.计算小鼠肺指数、湿干比值、肺组织切片HE染色观察其病理形态变化,ELISA法检测感染后第6天血清中IL-6、LTB4和ICAM-1的含量.免疫组化法检测肺组织水通道蛋白5（AQP5）蛋白表达水平.结果 流感病毒感染小鼠肺指数和湿干比值明显升高、肺组织间质炎性细胞渗出,以中性粒细胞浸润为主,伴明显的肺泡充血、水肿,肺组织AQP5蛋白表达水平明显下降;而NHDC可明显逆转上述病理症状.结论 NHDC对流感病毒诱导的小鼠肺组织气血屏障损伤有明显的保护作用,其可能是通过上调AQP5蛋白表达而发挥作用.     

东北岩高兰中查耳酮类化学成分研究

目的研究东北岩高兰Empetrum nigrum var.japonicum全草的查耳酮类化学成分。方法采用硅胶柱色谱和高效液相色谱等方法进行化学成分分离,并经波谱数据分析鉴定化合物的结构。用MTT法测试单体化合物对宫颈癌He La细胞的抑制活性。结果从东北岩高兰甲醇浸泡液正己烷萃取物中分离得到6个化合物,分别鉴定为2′,5′-二羟基-3′-甲氧基-4′,6′-二甲基二氢查耳酮(1)、4′,5′-二羟基-2′-甲氧基-3′,6′-二甲基二氢查耳酮(2)、2′,4′-二羟基二氢查耳酮(3)、2′,4′-二羟基查耳酮(4)、2′-甲氧基-4′-羟基二氢查耳酮(5)、2′,4′,β-三羟基二氢查耳酮(6)。结论化合物1、2为新化合物,命名为岩高兰素A和B,化合物5、6为首次从该植物中分离得到。化合物6具有一定的抗肿瘤活性。     

新陈皮苷二氢查尔酮中有机溶剂残留量的检测

目的采用顶空毛细管气相色谱法测定新陈皮苷二氢查尔酮中有机溶剂丙酮、乙酸乙酯、甲醇、乙醇的含量。方法色谱柱为HP-Innowax弹性石英毛细管柱(30m×0.32mm,0.5μm),采用程序升温法。结果各组分质量浓度与峰面积的线性范围分别为11.59～115.9,13.25～132.5,11.12～111.2,11.68～116.8μg/mL(r均大于0.999),检测限分别为0.7,0.3,2.2,1.8μg/mL。结论顶空毛细管气相色谱法可用于控制新陈皮苷二氢查尔酮的质量。