Physicochemical characteristics and antioxidant activity of melanoidin pigment from the fermented leaves of Orthosiphon stamineus

Abstract

Abstract:The melanoidin pigment (OS-M) was isolated from fermented leaves of Orthosiphon stamineus Benth. (Lamiaceae), with a 0.37% yield (from dry plant weight), and characterised. OS-M is a phenolic polymer with a molecular weight of 4.4 kDa. Determination of basic physicochemical parameters using elemental analysis, functional group analysis, UV-Vis-and FTIR-spectroscopy of OS-M indicated that the isolated polymer was similar to typical melanoidins. Experimental data show that aromatic fragments dominate the OS-M structure, which also contains a small amount of aliphatic fragments.

Water-Soluble Melanoidin Pigment as a New Antioxidant Component of Fermented Willowherb Leaves (Epilobium angustifolium)

“…The elemental composition of EAM was 58.3% carbon, 4.3% hydrogen, 37.1% oxygen, and 0.2% nitrogen ( Table 3 ). The known data on plant melanoidins indicate similar data for melanoidins formed after fermentation of the leaves or herb of plants such as Camellia sinensis [ 10 ] and Orthosiphon stamineus [ 12 ].…”

“…Another independent structural parameter, δ, is an unsaturation criterion with a value ranked in the range from −12.5 (methane) to 16.67 (graphite) [ 72 ]. The melanoidin of E. angustifolium had a δ value of 5.4, close to those of Orthosiphon stamineus melanoidin (5.6) [ 12 ] and black tea melanoidins (4.5–4.8) [ 10 ] with a high level of aromaticity. Most melanoidins of non-fermentation origin showed smaller δ values (1.3–4.0), which is typical for the more aliphatic phenolic polymers.…”

“…A melanoidin similar in structure and biological activity was also isolated from Orthosiphon aristatus (Blume) Miq. (Java tea; Lamiaceae) [ 12 ].…”

“…The unstudied question of the nature of the pigment that causes the browning of E. angustifolium leaves after fermentation deserves special attention. The most likely explanation for this phenomenon is the formation of melanoidins, similar to those in the well-known fermented black tea [ 10 ] or Java tea drinks [ 12 ]. This suggests the presence of various types of biological activity in the pigment [ 11 ].…”

In Vitro Regeneration and ISSR-Based Genetic Fidelity Analysis of Orthosiphon stamineus Benth

“…This species has been reported to improve general health effectively, as well as to be a known remedy for kidney diseases, bladder inflammation, gout, and diabetes [2]. Other than that, O. stamineus is also used to treat rheumatism, tonsillitis, and menstrual disorder [3][4][5]. The leaves were found to possess diuretic [6,7] and anti-hypertensive activities [3,8].…”