Extraction optimisation,antioxidant activity and inhibition on α-amylase and pancreatic lipase of polyphenols from the seeds of Syzygium cumini

The objectives of this study were to determine the optimal extraction conditions of polyphenols from Syzygium cumini seeds by response surface methodology and investigate their antioxidant activity and inhibition on α-amylase and pancreatic lipase. As results, the optimal extraction conditions in the ultrasonic extraction process which maximised total polyphenols content, minimised the IC₅₀ values of α-amylase and pancreatic lipase were determined as follows: extraction time 60 min, ethanol concentration 63% and solvent/solid ratio 44 mL g⁻¹. The main phenolic compounds in partially purified fraction of Syzygium cumini seeds were catechin, epicatechin, kaempferol, gallic, 5-caffeoylquinic, caffeic and ferulic acids. In addition, the partially purified fraction inhibited 87.66 ± 5.55 and 86.61 ± 3.15% of α-amylase and pancreatic lipase, respectively. The results suggested that Syzygium cumini seeds could be explored as a natural antioxidant and could be used as a source of highly antidiabetic and anti-obesity bioactive compounds.     

Composition of clove (Syzygium aromaticum) bud oil extracted using carbon dioxide

Analysis of clove (Syzygium aromaticum L) bud oil extracted with liquid and supercritical carbon dioxide shows significant qualitative and quantitative compositional differences compared with oil obtained by the conventional hydrodistillation process. The parameters of pressure, temperature, contact time etc, and also the clove oil components, affect the extraction of the bud flavour from the spice.     

丁香、甘草与迷迭香的抑菌作用及其在酱油中的应用研究

该文研究了从丁香、甘草及迷迭香中提取抑菌防腐物质的方法及其抑菌效力、最低抑菌浓度(MIC)、活性pH范围及热稳定性等性能。经组合后取代苯甲酸应用于酱油防腐，存放2个月后检测卫生指标，全部合格。     

Antioxidant capacity and hydrophilic phytochemicals in commercially grown native Australian fruits

Hydrophilic phytochemicals and antioxidant capacities of eight commercially grown native Australian fruits were determined. Kakadu plum (Terminalia ferdinandiana) contained a 6-fold higher level of total phenolic compounds and quandong (Santalum acuminatum) a 1.9-fold higher level of total phenolic compounds (TP, Folin–Ciocalteu assay) than blueberry (Vaccinum sp., cv. Biloxi). Both fruits displayed superior oxygen radical-scavenging capacity (ORAC-H assay) that was, respectively 4.1-fold and 6.5-fold of that of blueberry. The total reducing capacity (TRC; ferric reducing antioxidant power (FRAP) assay) of Kakadu plum and quandong exceeded the TRC of blueberry, respectively, 13.1- and 2.3-times. The primary sources of antioxidant capacities in the evaluated fruits were phenolic acids (benzoic and cinnamic) and flavonoids (flavonols, flavanones and anthocyanins) tentatively detected by liquid chromatography–mass spectrometry (LC–PDA–MS/MS). A high level of vitamin C was recorded for Kakadu plum and Australian citrus fruits. The major organic acids detected were citric and malic acid.     

Antioxidant capacity and phenolic compounds in commercially grown native Australian herbs and spices

The antioxidant capacities and phenolic composition in six native, commercially grown, Australian herbs and spices were investigated. Tasmannia pepper leaf, followed by anise myrtle and lemon myrtle contained the highest levels of total phenolics (TP; 102.1; 55.9 and 31.4 mg gallic acid equivalents (GAE)/g dry weight (DW), respectively). Tasmannia pepper leaf exhibited the highest oxygen radical absorbance capacity (ORAC assay) followed by lemon myrtle and anise myrtle. Anise myrtle exhibited the highest total reducing capacity [TRC; Ferric Reducing Antioxidant Power (FRAP) assay], followed by Tasmannia pepper leaf and lemon myrtle. Australian bush tomato, with TP content of 12.4 ± 0.9 mg GAE/gDW and TRC of 206.2 μMol Fe⁺²/gDW, resembled the Chinese Barbary Wolfberry fruit. The TP content of Tasmannia pepper berry (16.86 mg GAE/gDW) was similar to that of black pepper, but it’s TRC was 25% lower. Cinnamic acids and flavonoids, tentatively identified by mass spectrometry, were identified as the main sources of antioxidant activities.     

Aqueous extraction kinetics of phenolic compounds from jamun (Syzygium cumini L.) seeds

In this study, aqueous extraction of phenolic compounds from jamun (Syzygium cumini L.) seed was undertaken. The effects of various parameters such as extraction temperature (34.8–85.2°C), extraction time (49.8–100.2 min), and liquid-to-solid ratio (9.8–60.2 mL/g) on the extraction yield, extract purity (i.e., total polyphenol content), and its antioxidant activities (1,1-diphenyl-2-picrlthydrazyl free radical scavenging assay and ferric reducing antioxidant power) were investigated. Response surface methodology was used to optimize the extraction conditions. The optimum extraction conditions (49.2°C, 89.4 min, and 51.6:1 mL/g) produced an extract with 17.3% extraction yield, high total polyphenol content (415 mg gallic acid equivalent/g dried extract) and significant antioxidant activity (IC₅₀: 35.4 ± 0.7 µg/mL). The high-performance liquid chromatography analysis of seed extract revealed the presence of gallic acid (90.8 mg/g dried extract), ellagic acid (36 mg/g dried extract), caffeic acid (26.07 mg/g dried extract), p-coumaric acid (0.26 mg/g dried extract), catechin (9.05 mg/g dried extract), epicatechin (0.42 mg/g dried extract), and quercetin (1.54 mg/g dried extract). Tannic acid (188.5 mg/g dried extract) was also identified as a major phenolic compound. The extraction kinetics was also studied and experimental data were fitted to four kinetic models such as first-order model, second-order model, Peleg’s model, and Minchev and Minkov model, to evaluate their applicability.     

蒲桃茎、叶和花挥发油化学成分的气相色谱-质谱分析

为扩大蒲桃的药用部位,用水蒸气蒸馏分别提取了蒲桃鲜叶、干叶、花及茎的挥发油,用毛细管气相色谱-质谱联用法结合计算机检索,对其化学成分进行分析和鉴定,结果表明,从蒲桃鲜叶、干叶、花及茎挥发油中分别鉴定出了39、35、34和23种化合物。用气相色谱峰面积归一法测定了各组分的相对质量分数,各占总峰面积的87.51%、87.53%、84.24%及96.84%。4种挥发油化学组成各有异同,但主要成分是丁香烯-5-醇、葎草-5,8-二烯-3-醇、十六酸和植醇。     

微波法和水蒸气蒸馏法提取丁香精油的研究

以丁香为原料,分别采用微波法和水蒸气蒸馏法提取精油,探讨微波萃取对丁香精油提取率和精油品质的影响。以丁香精油提取率为指标,通过正交试验优化微波提取条件,采用气相色谱-质谱(GC-MS)法鉴定其化学成分,并与水蒸气蒸馏法提取的精油进行比较。结果表明,微波萃取丁香精油的最佳工艺参数为微波功率300 W、料液比1∶4(m∶V)、微波时间25s、提取次数4,该条件下精油的提取率可达到20.65%,远远高于水蒸气蒸馏法的11.33%;从该精油中鉴定出19种成分,其中3种丁香精油有效成分的得率分别为丁香酚13.2%、石竹烯4.4%、乙酰基丁香酚2.2%,石竹烯和乙酰基丁香酚得率分别是水蒸气蒸馏精油的2.8倍和2倍。微波萃取是丁香精油较有效的提取方式。