A simple optical pH sensor based on immobilization, Dioscorea alata L. anthocyanin methanol extract, onto a pectin–chitosan polyelectrolyte complex (pectin–chitosan PEC), has been successfully fabricated. The optical pH sensor was manufactured as a membrane made of pectin–chitosan PEC and the extracted anthocyanin. This sensor has the highest sensitivity of anthocyanin content at 0.025 mg/L in phosphate buffer and 0.0375 mg/L in citrate buffer. It also has good reproducibility with a relative standard deviation (%RSD) of 7.7%, and gives a stable response at time values greater than 5 min from exposure in a buffer solution, and the sensor can be utilized within five days from its synthesis. This optical pH sensor has been employed to determine saliva pH of people of different ages and showed no significant difference when compared to a potentiometric method.

Buku ini memuat berbagai hal tentang koleksi sampel, analisis fitokimia, ekstraksi, isolasi senyawa dan uji aktivitas senyawa hasil isolasi. Buku ini diharapkan mampu membantu pembaca dalam pemahaman senyawa metabolis sekunder tumbuhan, terutama teknik isolasi. Apalagi kita ketahui bahwa semakin bertambahnya penduduk maka tekanan ini menyebabkan perambahan hutan dan tumbuhan semakin tidak terkendali, sehingga mengakibatkan terjadinya kepunahan berbagai spesies tumbuhan yang tidak dapat diperbaharui, sementara potensi tumbuhan tersebut belum pernah diteliti dan dikaji.

A simple optical pH sensor using the active compound anthocyanin (ACN), derived Ruellia tuberosa L. flower immobilized in a pectin membrane matrix, was been fabricated and employed to monitor the freshness of tilapia fish at room temperature and 4oC storage. The quantitative pH values were measured based on the UV-Vis spectroscopy absorbance. The optimum pectin weight and ACN concentrations were 0.1% and 0.025 mg/L. The sensor showed good sensitivity at 0.03 M phosphate buffer solution. The sensor’s reproducibility was evaluated using 10 replicate sensors where a standard deviation of 0.045 or relative standard deviation of 9.15 was achieved. The sensor displayed an excellent response after 10 minutes of exposure, possessing a response stability for 10 consecutive days. The decrease in pH value of the Tilapia fish from 7.3 to 5 was observed in a 48 hour test, which can be used as the parameter when monitoring fish freshness. Overall, this reported optical pH sensor has a novelty as it could be used to monitor the rigor mortis phase of fish meat, which is useful in food industry.

A simple optical pH sensor using the active compound anthocyanin (ACN), derived Ruellia tuberosa L. flower immobilized in a pectin membrane matrix, was been fabricated and employed to monitor the freshness of tilapia fish at room temperature and 4oC storage. The optimum pectin weight and ACN concentrations were 0.1% and 0.025 mg/L. The sensor showed good sensitivity at 0.03 M phosphate buffer solution. The sensor’s reproducibility was evaluated using 10 replicate sensors where a standard deviation of 0.045 or relative standard deviation of 9.15 was achieved. The sensor displayed an excellent response after 10 minutes of exposure, possessing a response stability for 10 consecutive days. The decrease in pH value of the Tilapia fish from 7.3 to 5 was observed in a 48 hour test, which can be used as the parameter when monitoring fish freshness.

Objective: The purpose of this research is to know the chemical compound from the n-hexane extract of Kulu (Artocarpus camansi Blanco) fruit peels and to know its antidiabetes activity against male Swiss Webster mice.Methods: Samples were macerated with n-hexane solvent, then the extracts were obtained, was characterization with gas chromatography-mass spectrometry (GC-MS), and then the extract separated by column chromatography. The results obtained were tested by antidiabetes action with glucose tolerance method.Results: Anti-diabetic activity test result showed that the most active sample to decrease the blood glucose of mice was n-hexane crude extract, at minute 90th, activeness was 65.59%, compared to glibenclamide, then group of fraction A, at minute 90th, activeness 65.58% compared glibenclamide, whereas isolate D11, its activity is 60.11% and 60.12%, at minute 60th and 90 min compared to glibenclamide. Concentrated extracts were characterized by GC-MS, shows the major compounds are hexadecanoic acid methyl ester (30.14%), 9,12-octadecadienoyl chloride, (Z, Z) - (8.44%) and 9-octadecenoic acid, methyl ester (30,91%) also were obtained a compound like an β-amyrin acetate.Conclusion: The most active sample to decrease the blood glucose of mice was n-hexane crude extract, and the major compounds are hexadecanoic acid methyl ester (30.14%), 9,12-octadecadienoyl chloride, (Z, Z) - (8.44%) and 9-octadecenoic acid, methyl ester (30.91%).