Table 3.

Oral microbial metabolites and the affected biochemical metabolic pathway in OSCC.

Carbohydrates	Amino Acids	Organic Acids	Fatty Acids	Lipids	Amines	Amides	Metabolic Pathway	Ref.
N-Acetyl-D-glucosamine	N-Acetyl-L-phenylalanine, D-Alanyl-D-alanine, Palmitoyl-L-carnitine, N-Glycyl-L-proline, L-Carnitine	L-Pipecolic acid		phosphorylcholine	Deoxyguanosine		Glycolysis, Phospholipid and choline metabolism, Fatty acid oxidation, Oxidative stress biosynthesis	[124]
	5,5-diethylpentadecane, L-proline	decanedioic acid, 2-methyloctacosane, Eicosane, Octane, 3,5-dimethyl, pentadecane, hentriacontane, nonadecane, oxalic acid, 6-phenylundecanea, 2-furancarboxamide, 2-isopropyl-5-methyl-1-heptanol, pentanoic acid, docosane					Amino acid metabolism Organic acid metabolism	[125]
N-acetylglucosamine	proline, carnitine, 5-hydroxylysine, 3-methylhistidine				adenosine, inosine			[126]
maltose, dihydroxyacetone phosphate, galacturonic acid, ribose 5-phosphate, lactose	methionine, inosine, uracil, o-phospho-serine, pantothenic acid, leucine			malic acid, protocatechuic acid, 2-ketoglutaric acid, catechol, 2-ketoadipic acid, margaric acid, palmitic acid, maleic acid	indole-3-acetic acid, spermidine	urea	Malate-Asparate shuttle pathway, Warburg effect pathway, Beta-alanine pathway	[127]
	histidine, tyrosine, glycine, glutamic acid, aspartic acid, tryptophan, lysine, methionine, gamma-aminobutyric acid (GABA), urocanate, 2-isopropaylate, 2-aminobutyric acids		butyrate				TCA cycle, Tryptophan metabolism	[128]
fucose	taurine, glycine, aspartate, cisaconitate, glycine	methanol	propionate, isobutyrate, acetoacetate	choline	trimethylamine N-oxide		Tryptophan and Nicotinamide pathway	[129]
N-acetylglucosamine	creatinine, 5-aminovalerate, pipecolate, gamma-butyrobetaine, 2′-deoxyinsine, N-acetylhistidine, o-acetylcarnitine	N-acetylputrescine, indole-3-acetate		ethanolamine phosphate	trimethylamine N-oxide, putrescine, N1-acetylspermine		Methane, Purine, Glutathione, lysine, sphingolipid, Arginine, proline, Glycerophospholipid metabolism	[94]
glucose	cadaverine, serine	5-aminopentoate, hippuric acid		phosphocholine, adrenic acid	putrescine, thymidine, adenosine		Amino acid biosynthesis, Arginine and proline pathway, histidine, lysine pathway	[130]
N-acetylglucosamine-1-phosphate, ribose 5-phosphate (R5P)	carnitine arginine	o-hydroxybenzoate		ornithine			Pentose–phosphate pathway	[131]
3-heptanone, pentanone, butyrolactone		1,3-butanediol, 1,2-pentanediol, 1-hexadecanol, ethanol, 2-phenol, 1-octanol, benzyl alcohol		hexadecanoic acid, undecane			Fatty acid biosynthesis	[132]
d-glycerate-2-phosphate, 4-nitroquinoline-1-oxide, inositol 1,3,4-triphosphate, neuraminic acid	1-methyl histidine, 2-oxoarginine, norcocaine nitroxide, p-chlorphenylalanine, N-(3-Indolylacetyl)-l-isoleucine, l- homocysteic acid, ubiquinone	S-ureidoglycolic acid, d-urobilinogen		estrone-3-glucuronide, sphinganine-1 phosphate, tetradecanedioic acid, 1-hexadecyl hexadecanoate, estradiol valerate	pseudouridine		Amino acid, Carbohydrate, Estrogen, Spingolipid metabolism, Oxidative stress, Neucleotide biosynthesis pathway, Electron transport	[133]
	glycine, proline, citrulline			ornithine			TCA cycle, Threonine, Arginine and proline pathway	[134]
fucose	Proline	1,2 propanediol					Carbohydrate and Amino acid metabolism	[135]
		1,4-dichlorobenzene, 1,2-decanediol, 2,5-Bis1, 1-dimethylethylphenol, E-3-decen-2-ol, 2,4-dimethyl-1-heptene, 1-chloro-2-propanol, 1-chloro-2-butanol, 2-propenoic acid, 2,3,3-trimethylpentane, ethanol, 1,2,3,4-tetrachlorobutane	propanoic acid (ethyl ester), acetic acid, propanoic acid, ethyl acetate				Amino acid metabolism, Propanoate metabolism, Glycolysis, Pyruvate, Sulphur and Taurine metabolism, Nicotinate pathway, Ketone bodies pathway	[136]
3-phenyllactic acid	2-hydroxy-4-methylvaleric acid, valine, leucine, butyrobetaine, isoleucine, tryptophan, 3-phenylpropionic acid, cadaverine, N6,N6,N6-trimethyllysine, taurine, alanine	p-hydroxyphenylacetic acid, hexanoic acid, octanoic acid, terephthalic acid, glycolic acid, heptanoic acid	3-propionic acid, butyric acid, 2-oxoisovaleric acid	choline		urea	Urea cycle	[137]
3-phosphoglyceric acid	pipecolate. methionine, S-adenosylmethionine, tryptophan, valine, hypoxanthine, glycylglycine, taurine, cadaverine			choline	spermidine, 2-aminobenzamide, trimethylamine N-oxide, guanine, guanosine, threonine		Polyamine synthesis	[138]
	L-phenylalanine and L-leucine						TCA cycle, Fat metabolism	[139]
	betaine, L-carnitine	pipecolinic acid		choline			Lipid, Lysine and Fatty acid metabolism	[140]
	N-nonanoylglycine, hexanoylcarnitine, carnitine, 4-hydroxy-L-glutamic acid, acetylphenylalanine, S-carboxymethyl-L-cystein	lactic acid, hydroxyphenynactic acid, succinic acid		ornithine, propionylcholine, spihingarine, phytosphingosine	hydroxymethyluracil		Amino acid metabolism, Fatty acid and carbohydrate metabolism, TCA cycle, Urea cycle	[141]
	alanine, 3-indolepropionic acid, valine, proline, isoleucine, leucine, proline, threonine, phenylalanine, γ-aminobutyric acid	lactic acid,		n-eicosanoic acid, n-tetradecanoic acid			Krebs cycle	[123]
	pyrroline hydroxycarboxylic acid, leucine plus isoleucine, tryptophan, valine, threonine, histidine, pipecolic acid, glutamic acid, carnitine, alanine, taurine, C4H9N and C8H9N, phenylalanine betaine, serine, tyrosine, glutamine, beta-alanine, cadaverine, C5H14N5, C4H5N2O11P		alpha-aminobutyric acid	choline	piperideine, C6H6N2O2,		Phospholipid pathway	[142]
	Vitamin B and C						Lipid peroxidation	[143]