Free radical scavenging of Juwet (Syzgium cumini) Fruit

Juwet  are also known as jamblang, duwet, jambolan, java plump, belongs to the family mrytaceae. This plant rarely known by today's young generation. The colour of Juwet fruit are green, red, purple, or black-blue according to their level of ripeness, sour, sweet,  are the taste of Juwet.

The purple to black colour of Juwet indicates a high anthocyanin content. This is related to differences in the interaction of anthocyanin compounds with various metal ions such as Al, Fe, and Mg. Various anthocyanin content which is one of the antioxidant compounds in juwets such as malvidin, petunidin, delphinidin, cyaniding, petonidin, and pelargonidin. These compounds are easy to form complex compounds with metal ions because it has a hydroxyl group and other groups at certain positions in the aromatic ring. These complex compounds of antioxidants and metals have a stronger ability to fight free radicals    compared to single compounds.
           Free radicals are molecules that lose an electron pair so that it is reactive to find new electron pairs. The electrons in their orbitals surround the nucleus and rotate on their axis. Electrons surround, or orbit an atom in one or more layers and spin on the axis occurs in two opposite directions from left to right (Spin down) and from right to left (spin up) so that all electrons in orbitals are paired with spin in opposite directions. Paired electrons in orbitals with opposite spin directions indicate the stable condition of an atom. Electrons in stable condition have diamagnetic properties. The opposite is a condition where an atom does not have paired electrons, so that the rotation of electrons in parallel or in the same direction in orbitals will cause a magnetic field with paramagnetic properties.

In our body the electron pair is obtained from compounds or molecules in cells that are nearby so that the cell will undergo structural changes and malfunction and can cause new free radicals. Overcoming this antioxidant is needed. Antioxidants are compounds that function to neutralize free radicals through the transfer or donor of electrons to free radicals. Free radicals first react with antioxidants so that the body's tissue is protected from free radicals.
This structure is known to easily chelate transition metals and become ligands in complex compounds or bioinorganic compounds that are formed. Anthocyanin is a polyphenol compound consisting of 15 carbon atoms with a C6-C3-C6 structure with two aromatic rings marked with ring A and ring B and both are connected by ring C. Hydroxyl groups, sugar, oxygen or methyl groups are attached to the ring. free radical scavenging flavonoids and anthocyanins such as Cyanidin due to the delocalisation of the B ring (and the presence of hydroxyl groups. This group functions as an electron source through the mechanism of the hydrogen atom donor or single electron transfer. Cyanidin-3,5-O-diglucoside is one of the anthocyanins from juwet in catechol group which contains OH groups (C3'C4 ') in ring B. This structure makes it easy for Cyanidin-3,5-O-diglucoside to chelate metal and form compounds complex. Compounds or bioinorganic compounds of the naturally formed juwet fruit consist of transition metal cations and ligands. Ligands are molecules or ions that are bound to transition metal cations. The interaction between transition metal cations with ligands is a Lewis acid-base reaction. According to Lewis, the ligand is a Lewis base that acts as an electron donor. While the transition metal cation is a Lewis acid which acts as an electron receiver. This results in a coordinated covalent bond between the ligand and the transition metal cation in the process of complex ion formation. The Fe^{2 +} or Fe^{3 +} ions are able to coordinate with the three catechol or gallate groups of polyphenols to form complex compounds with octahedral geometry. Polyphenols chelate Fe^2+, then undergo an autoxidation process to form Fe^{3 +} - polyphenol complexes that are more stable than Fe^{2 +} . Physically, Fe^{2 +} and Fe^{3 +} in this case are part of the scavenger mechanism, namely the change in magnetic properties from paramagnetic to complex diamagnetic compounds when losing or getting electrons from free radicals.