artificial flavoring
Refers to synthetic substances used to impart flavor to food, beverages, or other products.
Artificial flavoring is used in this candy.
synthetic perfume
Refers to man-made fragrance compounds used in perfumes, cosmetics, or scented products.
That perfume is made with synthetic perfume, not natural fragrance.
天然香料 refers to natural flavoring or fragrance derived from plants or animals, while 人工香料 is synthetic.
Compound of 人工 (じんこう, 'artificial') and 香料 (こうりょう, 'flavoring' or 'fragrance').