Protective effects of peel and seed extracts of Citrus aurantium on glutamate-induced cytotoxicity in PC12 cell line.

Oxidative stress and apoptosis contribute to neuronal degeneration in many neurodegenerative diseases such as Alzheimer's disease. Glutamate is a major excitatory neurotransmitter in the central nervous system (CNS) and is considered responsible for the pathogenesis of many neurological disorders. Reactive oxygen species (ROS) production is thought to be involved in glutamate-induced apoptosis process. In this study, the neuroprotective effects of Citrus aurantium in the glutamate-induced rat's adrenal pheochromocytoma cell line (PC12 cells) were investigated. The cell viability and apoptotic cell death were measured using MTT and propidium iodine (PI)-staining methods, respectively. In addition, intracellular ROS and malondialdehyde (MDA) levels were determined by fluorometric methods. The results showed that glutamate cytotoxicity in PC12 cells was accompanied by an increment of MDA content, ROS generation, and apoptotic induction. However, pretreatment with peel and seed extracts of C. aurantium significantly reduced MDA content, ROS generation, and apoptotic cells. All these findings indicated that C. aurantium protected PC12 cells against glutamate-induced apoptosis by inhibiting ROS production. Therefore, the present study supports that C. aurantium extracts possess neuroprotective effects against glutamate-induced toxicity in PC12 cell line. The protective effect of C. aurantium might be attributed to its antioxidant properties.

Resistance to pathogens in terpene down-regulated orange fruits inversely correlates with the accumulation of D-limonene in peel oil glands.

Volatile organic compounds (VOCs) are secondary metabolites acting as a language for the communication of plants with the environment. In orange fruits, the monoterpene D-limonene accumulates at very high levels in oil glands from the peel. Drastic down-regulation of D-limonene synthase gene expression in the peel of transgenic oranges harboring a D-limonene synthase transgene in antisense (AS) configuration altered the monoterpene profile in oil glands, mainly resulting in reduced accumulation of D-limonene. This led to fruit resistance against Penicillium digitatum (Pd), Xanthomonas citri subsp. citri (Xcc) and other specialized pathogens. Here, we analyze resistance to pathogens in independent AS and empty vector (EV) lines, which have low, medium or high D-limonene concentrations and show that the level of resistance is inversely related to the accumulation of D-limonene in orange peels, thus explaining the need of high D-limonene accumulation in mature oranges in nature for the efficient attraction of specialized microorganism frugivores.

Validated reversed phase LC method for quantitative analysis of polymethoxyflavones in citrus peel extracts.

Polymethoxyflavones (PMFs), which exist exclusively in the citrus genus, have biological activities including anti-inflammatory, anticarcinogenic, and antiatherogenic properties. A validated RPLC method was developed for quantitative analysis of six major PMFs, namely nobiletin, tangeretin, sinensetin, 5,6,7,4'-tetramethoxyflavone, 3,5,6,7,3',4'-hexamethoxyflavone, and 3,5,6,7,8,3',4'-heptamethoxyflavone. The polar embedded LC stationary phase was able to fully resolve the six analogues. The developed method was fully validated in terms of linearity, accuracy, precision, sensitivity, and system suitability. The LOD of the method was calculated as 0.15 microg/mL and the recovery rate was between 97.0 and 105.1%. This analytical method was successfully applied to quantify the individual PMFs in four commercially available citrus peel extracts (CPEs). Each extract shows significant difference in the PMF composition and concentration. This method may provide a simple, rapid, and reliable tool to help reveal the correlation between the bioactivity of the PMF extracts and the individual PMF content.

[Genetic relationships among Fructus Aurantii cultivars revealed by ISSR].

OBJECTIVE: A total of 27 samples belonging to 5 cultivars of Fructus Aurantii (Citrus aurantium), i. e. cv. Xiucheng, cv. Xiangcheng, cv. Lecheng, cv. Jizicheng, and cv. Youzicheng, collected at Changfu and Huanggang, Zhangshu City, Jiangxi Province, were assayed to reveal the genetic relationship among the cultivars and the accordance between morphological and molecular markers. METHOD: Cultivar identification was based on morphology and cultivar relationship was based on Inter-simple sequence repeats (ISSR). RESULT: Twenty out of 40 ISSR primers screened generated 392 loci across all 27 samples with 315 informative loci. The UPGMA dendrogram showed that samples within cv. Xiucheng and cv. Xiangcheng from Changfu were closely related. However, samples of cv. Lecheng, cv. Jizicheng and cv. Youzicheng from Huanggang, or cv. Xiucheng and cv. Xiangcheng from both Changfu and Huanggang did not exhibited close relationships within each cultivars. CONCLUSION: Based on morphology the same cultivar grown in different plantations, or even within a single plantation sometimes do not show close genetic relationship, indicating diverse origin of the cultivars. Synonyms or homonyms are believed to common phenomenon in Fructus Aurantii production. To solve the problem ISSR markers can serve a kind of molecular markers which are preferable to partition genetic variations within and between cultivars and to establish genetic relationships among them.

[Descriptions and microscopy identification of Citrus grandis var. tomentosa Hort. and Citrus grandis Osbeck].

OBJECTIVE: To identify Citrus grandis var. tomentosa Hort. and Citrus grandis Osbeck. METHODS: Descriptions and microscopy identification. RESULTS: There are nonglandular hair in the stem epidermis, many starch grains in the stem cortex and many prismatic crystals of calcium oxalate in the phloem of C. grandis var. tomentosa Hart. The palisade tissues of the leave are thick. The outer layer palisade tissues contains prismatic crystals. The cortex of leaf vein is thick. The other characters are similar to C. grandis Osbeck. CONCLUSION: Above-mentioned characters can be used to identify C. grandis var. tomentosa Hort. and C. grandis Osbeck.

[Histological identification of Chinese drug zhiqiao & zhishi].

After growing area investigating which covered 10 Provinces (or Cities) of China, we gathered 11 types Zhiqiao and 6 types Zhishi which consistently came from 12 species (or varieties). Histological studies on them have been taken. microscopical characters including transverse section and powder were described. These studies will provide scientific basis for the identification of Zhiqiao and Zhishi.

[Studies on Chinese drugs zhiqiao and zhishi origin investigation and merchandise identification].

OBJECTIVE: To sort out the main original plants of Chinese drugs Zhiqiao and Zhishi. METHOD: Investigating the medicinal plant resources in the growing area and conducting morphological identification of more than 40 pieces of these two commercial drugs. RESULT: A taxonomic table, a distribution table and a commercial drug identification table are given. CONVLUSION: The Chinese medicinal plants Zhiqiao and Zhishi originated from Citrus aurantium and its varieties C. aurantium "Xiucheng", C. aurantium "Xiangcheng" and Poncirus trifoliata x C. aurantium, some other plants from Citrus genus and Poncirus trifoliata are taken as the origin of Zhiqiao and Zhishi only in a few areas.

[Textual studies on shangzhou zhiqiao fructus Aurantii].

The original plant of Shangzhou Zhiqiao, the best among the species of Zhiqino, is confirmed as Citrus aurantium rather than Poncirus trifolia in this paper based on the description and drawings of Zhiqiao in (Bencao Gangmu) by Li Shizhen in the 16th rentury, samples from Shangzhou(Shanxi Province), and the cold-warm period of historical climate in the local area, which is believed to be related to the distribution of C. aurantium in Shangzhou. However, P.trifolia has often been confused with C. aurantium by some herbalists.