Curcuma aeruginosa Roxb. is one of the plants from the Zingiberaceae family which the rhizome has been used for medicinal purposes. However, the biological properties of the leaves have not been fully explored. Therefore, this study was conducted to evaluate the effects of different drying methods and solvents on total phenolic content, antioxidant and anti-hyperglycemic activities of C. aeruginosa leaf extract. Samples were dried by oven drying (OD) and freeze drying (FD), and then extracted using different ratios of ethanol:water (100:0, 50:50 and 0:100). The amount of phenolic content (TPC) was determined using a spectrophotometer. Antioxidant activity was tested using the Free Radical Scavenging (DPPH) test and the Ferric Reducing Antioxidant Power assay (FRAP), while the anti-hyperglycemic test was evaluated by determining the percentage of α-glucosidase inhibition. The results showed that FD at 100:0 and 50:50 concentrations had the highest phenolic content (30.88 and 33.06 mg GAE/g extract, respectively) and highest antioxidant activity value (38.24 and 42.46 mg TEAC/g extract, respectively). For DPPH, FD at 50:50 showed the highest inhibition of 71.48% compared to other extracts. Whereas FD at 100:0, 50:50 and 0:100 showed the highest α-glucosidase inhibition of 25.65, 30.78 and 27.65%, respectively. However, compared to Quercetin, the extract showed mild anti-hyperglycemic activity. The results indicated that FD is the best method of drying while 50:50 showed as the best solvents. Positive correlation between TPC with antioxidant and anti-hyperglycemic activities showed that C. aeruginosa leaf has potential as a source of natural antioxidant with the presence of phenolic compounds.

Plants are the primary source of the food chain and are rich in nutrients and biochemical compounds that mainly give beneficial effects to humans as well as other living organisms. Curcuma caesia Roxb. is a family member of Zingiberaceae commonly known as black turmeric. The leaves and rhizomes of this plant are extensively used in Ayurvedic medicine and as traditional remedies for various ailments. The aromatic rhizomes and leaves are due to the presence of essential oils reported as camphor, ar-turmerone, (Z)-β-ocimene, ar-curcumene, 1,8-cineole, β-elemene, borneol, bornyl acetate, tropolone, ledol, β-elemenone, and α-bulnesene. Previous research studies have revealed most of the biological activities of C. caesia, such as antioxidant, antimicrobial, and anti-inflammatory properties, which are due to the presence of various bioactive components. The diverse chemical composition contained in this plant contributes to various biological activities, which may be beneficial for the health, food, and cosmetic industries. The purpose of this review was to summarise updated research on the in vitro and in vivo activities of C. caesia as well as the current clinical investigations. A compilation of the latest findings regarding the potential activities of C. caesia and mechanisms related to its health benefits is discussed and reviewed. This valuable information is the key that can be used for the development of drugs, functional food ingredients, and food products.

Kombucha adalah sejenis minuman yang terhasil daripada penapaian teh manis dengan menggunakan kultur simbiotik bakteria dan yis. Fukoidan merupakan sejenis polisakarida fungsian daripada rumpai laut yang dipercayai mempunyai kesan kesihatan yang baik. Penyelidikan ini telah dijalankan bertujuan untuk mengetahui kesan kepekatan fukoidan (0, 0.25, 0.5, 0.75 dan 1.00 mg/mL) dan hari penapaian yang berbeza terhadap sifat fizikokimia (pH, jumlah pepejal terlarut (TSS), warna, kandungan fenol jumlah (TPC), kandungan flavonoid jumlah (TFC), kandungan gula, kandungan alkohol dan keasidan boleh titrat (TA)) serta kualiti kimia kombucha yang diperkaya dengan fukoidan. Nilai pH sampel kombucha menurun dengan ketara (p<0.05) apabila tempoh penapaian berpanjangan. Penambahan fukoidan mempengaruhi warna L *, a *, dan b * tanpa corak tertentu. Tempoh penapaian yang lebih lama meningkatkan kecerahan, namun mengurangkan kemerahan dan kekuningan semua sampel kombucha. Sementara itu, kandungan TSS dan gula sampel kombucha berkadar songsang dengan tempoh penapaian, kecuali bagi kombucha (0.75 mg/mL) yang dicatatkan lebih tinggi (p <0.05) nilai TSS daripada kombucha (0.25 mg/mL fukoidan) pada hari ke 14. Bagaimanapun, tiada kesan signifikan (p>0.05) penambahan kombucha yang diperkuat dengan fukoidan terhadap gula. Secara keseluruhan, jumlah kandungan fenol dan flavonoid meningkat(p<0.05) dengan penambahan fukoidan dan tempoh penapaian, manakala peratusan TA dan kandungan etanol kombucha meningkat dengan tempoh penapaian berpanjangan. Kesimpulannya, sampel kombucha mengalami perubahan fizikokimia dan peningkatan jumlah kandungan fenol dan flavonoid selari dengan tempoh penapaian. Kajian ini menunjukkan bahawa fukoidan berpotensi digunakan sebagai bahan berfungsi dalam minuman kombucha.

Research background. Curcuma species (Zingiberaceae) are well known medicinal herbs in India and Southeast Asia. Despite various findings reporting their beneficial biological activities, very little information has been recorded on the Curcuma caesia. Thus, this study aims to determine the phenolic content, antioxidant and α-glucosidase inhibitory activity of both rhizome and leaves of C. caesia. Experimental approach. Rhizome and leaves of C. caesia were dried with oven (OD) and freeze (FD) drying methods, and extracted with different ethanol/water ratios of 0/100, 50/50, 80/20 and 100/0. The bioactivities of C. caesia extracts were evaluated using in-vitro tests; total phenolic content (TPC), antioxidant (DPPH and FRAP) and α-glucosidase inhibitory activity. Proton nuclear magnetic resonance (1H NMR)-based metabolomics approach was employed to differentiate the most active extracts based on their metabolite profiles and correlation with bioactivities. Results and conclusions. The 100/0 FD rhizome extract was observed to have potent TPC, FRAP and α-glucosidase inhibitory activity with values of (45.38±2.10) mg GAE/g extract, (147.73±8.26) mg TAE/g extract and (265.46±38.62) µg/mL (IC50), respectively. Meanwhile, for DPPH scavenging activity, the 80/20 and 100/0 extracts of FD rhizome showed the highest activity with no significant difference between them. Hence, the FD rhizome extracts were selected for further metabolomics analysis. Principal component analysis (PCA) showed clear discrimination among the different extracts. Partial least square (PLS) analysis showed positive correlations between the metabolites, including xanthorrhizol derivative, l-hydroxy-1,7-bis(4-hydroxy-3-methoxyphenyl)-(6E)-6-heptene-3,4-dione, valine, luteolin, zedoardiol, β-turmerone, selina-4(15),7(11)-dien-8-one, zedoalactone B and germacrone, with the antioxidant and α-glucosidase inhibition activities. Meanwhile, curdione and 1-(4-hydroxy-3,5-dimethoxyphenyl)-7-(4-hydroxy-3-methoxyphenyl)-(lE,6E)-1,6-heptadiene3,4-dione were correlated with α-glucosidase inhibitory activity. Novelty and scientific contribution. C. caesia rhizome and leaves extracts contained phenolic compounds and had varies antioxidant and α-glucosidase inhibitory capacities. These findings strongly suggests that the rhizomes of C. caesia are an invaluable natural source of active ingredients for applications in pharmaceutical and food industries.