Exogenous stimulation-induced biosynthesis of volatile compounds: Aroma formation of oolong tea at postharvest stage.

Volatile organic compounds (VOCs) are produced by plants responding to biotic and abiotic stresses. According to their biosynthetic sources, induced VOCs are divided into three major classes: terpenoids, phenylpropanoid/benzenoid, and fatty acid derivatives. These compounds with specific aroma characteristics importantly contribute to the aroma quality of oolong tea. Shaking and rocking is the crucial procedure for the aroma formation of oolong tea by exerting mechanical damage to fresh tea leaves. Abundant studies have been carried out to investigate the formation mechanisms of VOCs during oolong tea processing in recent years. This review systematically introduces the biosynthesis of VOCs in plants, and the volatile changes due to biotic and abiotic stresses are summarized and expatiated, using oolong tea as an example.

Discrimination of Chinese teas with different fermentation degrees by stepwise linear discriminant analysis (S-LDA) of the chemical compounds.

This study aimed to construct objective and accurate analytical models of tea categories based on their polyphenols and caffeine. A total of 522 tea samples of 4 commonly consumed teas with different fermentation degrees (green tea, white tea, oolong tea, and black tea) were analyzed by high-performance liquid chromatography (HPLC) coupled with spectrophotometry, utilizing ISO 14502, as analytical tools. The content of polyphenols and caffeine varied significantly according to differently fermented teas, indicating that these active constituents may discriminate fermentation degrees effectively. By principal component analysis (PCA) and stepwise linear discriminant analysis (S-LDA), the vast majority of tea samples could be successfully differentiated according to their chemical markers. This study yielded three discriminant functions with the capacity to simultaneously discriminate the four tea categories with a 97.8% correct rate. In classification of oolong and other teas, there were one discriminant function and two equations with best discriminant capacity. Furthermore, the classification of different degrees of fermentation of oolong and external validation achieved the desired results. It is suggested that polyphenols and caffeine are the distinct variables to establish internationally recognized models of teas.

Evaluation of capecitabine and oxaliplatin administered prior to and then concomitant to radiotherapy in high risk locally advanced rectal cancer.

BACKGROUND AND OBJECTIVES: Systemic failure remains a predominant issue in locally advanced rectal cancer (LARC). A new strategy using capecitabine and oxaliplatin (XELOX regimen) administered prior to and then concomitant to radiotherapy for high risk LARC is developed in our practice. The aim of the present study was to evaluate the short-term efficacy and toxicities of this strategy. METHODS: Patients were treated with one cycle XELOX regimen (oxaliplatin 130 mg/m(2) on day 1 with capecitabine 1,000 mg/m(2) twice daily for 14 days every 3 weeks), followed by chemoradiation (50 Gy over 5 weeks) with modified XELOX regimen (oxaliplatin dose reduction to 100 mg/m(2)), and total mesorectal excision. Tumor response, toxicities, and surgical complications were recorded. RESULTS: Forty-two patients treated with the strategy were identified. All patients completed planned dose of induction chemotherapy and concurrent chemoradiotherapy. Grade 3 toxicities were thrombocytopenia (4.8%), diarrhea (7.1%), proctitis (4.8%), and radiation dermatitis (7.1%). Five patients (12.5%) developed postoperative complications. Pathologic complete response (pCR) and nearly pCR were achieved in 7 (15.0%) and 13 patients (35.0%). CONCLUSIONS: The preliminary results suggest that induction chemotherapy followed by chemoradiotherapy with capecitabine and oxaliplatin in LARC is well tolerated. The strategy achieves favorable short term outcome in terms of pCR and nearly pCR rate, which warrants further investigation.