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This study was designed to develop a cost effective green extraction method to separate valuable chemicals from black tea waste (BTW) and tea dust called "caffeine dust" (CD). These materials are totally unwanted residue and treated as rubbish. Two extraction methods were used for extraction of waste materials obtained in three collection periods. In conventional extraction method, material was subjected to hot water extraction at 80 o C for 40 minutes. In microwave assisted extraction (MAE) method, different eco-friendly aqueous solvents (water, citric acid-water or ethanol-water) were used under a controlled 600 W microwave power at 80 o C for only 4 minutes treatment in a close microwave system. MAE and conventional method gave similar extract yields for both waste materials but MAE was more successful and economical completing the extraction in shorter time. Using citric acid-water solvent in MAE significantly increased the extraction of individual catechins such as epicatechin (EC) and epigallocatechin gallate (EGCG). This study showed that tea waste could be utilized for production of valuable chemicals using nontoxic solvents at extremely short extraction periods.

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In this study, hexane, chloroform and water extracts were prepared by making consecutive extraction of Achillea biserrata from the family Asteraceae. Volatile oil of the same types was obtained by water distillation that was continued 4 hours in the Clevenger fixture and dried by adding anhydrous sodium sulfate. After GS/MS analysis, volatile oil of the same types was kept at 4 ºC in the refrigerator and dark until the work activity was performed. Volatile oil yield that was obtained from mixture of all dried flower and plant leaves were determined for Achillea biserrata 0.4%(v/w) The antioxidant activities of extracts, total phenol, flavonoid, proanthocyanidin and anthocyanin amounts were determined. Two different tests were performed for measurements of antioxidant activities. 1 Especially, for the purpose of meeting the general properties of good additives' free radical cleaning activity was done by DPPH method and the inhibition of oxidation activity was done by with β-carotene method. The 50% inhibition (IC 50 ) values of the water, methanol:water and chloroform extracts were 19.6, 37.9 and 114 μg /mL, respectively ın DPPH test. Besıdes, the nonpolar extracts were active in β-carotene/linoleic acid test system. Total phenolics and total flavonoid contents were highest in the water extract possessing 3.39% and 1.12%, respectively. Methanolic extract showed the presence of antioxidant phenolic compounds such as protocatecuic acid (177.83 g/g) and chlorogenic acid (164.78 g/g) ın HPLC analsıs. Automated extraction system obtained better separation of the active principles from plant tissues than conventional extraction procedures.

Effective extraction of anticancer and antioxidant principles from Turkish green tea were main purpose of this work. The pre-optimized experimental condition for liquid extraction was employed for comparative appraisal. Not only extraction methods also nature of the green tea samples (fresh, dried or frozen) and quantitative yields related to collection periods were investigated. After extraction of the green tea with various techniques the extract was partitioned with chloroform to remove caffeine, after that the extract was partitioned with ethyl acetate to obtain catechin mixture. Quantification of individual catechins was carried out by HPLC and analysis results proved that epigallocatechin gallate (EGCG) was main catechin specie present in all extracts. The results indicate that hot water extraction (at 80 0 C) provides higher catechin yield when compared to other methods. The highest extract yields were obtained with dried leaves collected in second collection period. The crude catechin mixture contains high amount of EGCG and might be used as raw material for production of plant remedies at industrial scale.