Nicotinamide (Vitamin B3)

Nicotinamide (Vitamin B3) is an amide derivative of vitamin B3 that can inhibit the activity of SIRT1 (IC₅₀: 50-180 μM) and SIRT2 (IC₅₀: 2 μM). Nicotinamide can also increase the levels of NAD⁺, ATP, and ROS in cells ^[3].

Nicotinamide (5mM ,72h) treat senescent fibroblasts cells reduces ROS levels and the appearance of senescence phenotypes in senescent fibroblasts^[1]. Nicotinamide (50-200μM) treat HepG2 cells enhanced NAD⁺ biosynthesis in a dose-dependent manner^[4] .

Nicotinamide (0.5/1.0 mg/kg) Treatment Alters Whole-Body Physiology and In Vivo Metabolism without Affecting Maximum Lifespan^[2]. Long-Term Nicotinamide（300 mg/kg/day；between 6 and 12 months） Administration Reverses Age-Associated Gene Expression Changes in Peripheral Tissues and Enhances Mitochondrial Respiratory Capacity in Skeletal Muscle^[5].

References:
[1]. Kwak JY, Ham HJ, Kim CM, Hwang ES. Nicotinamide exerts antioxidative effects on senescent cells. Mol Cells. 2015 Mar;38(3):229-35.
[2]. Mitchell SJ, Bernier M, Aon MA, Cortassa S, Kim EY, Fang EF, Palacios HH, Ali A, Navas-Enamorado I, Di Francesco A, Kaiser TA, Waltz TB, Zhang N, Ellis JL, Elliott PJ, Frederick DW, Bohr VA, Schmidt MS, Brenner C, Sinclair DA, Sauve AA, Baur JA, de Cabo R. Nicotinamide Improves Aspects of Healthspan, but Not Lifespan, in Mice. Cell Metab. 2018 Mar 6;27(3):667-676.e4.
[3].Hwang ES, Song SB. Nicotinamide is an inhibitor of SIRT1 in vitro, but can be a stimulator in cells. Cell Mol Life Sci. 2017 Sep;74(18):3347-3362. 
[4]. Yoshino J, Mills KF, Yoon MJ, Imai S. Nicotinamide mononucleotide, a key NAD(+) intermediate, treats the pathophysiology of diet- and age-induced diabetes in mice. Cell Metab. 2011 Oct 5;14(4):528-36.
[5]. Mills KF, Yoshida S, Stein LR, Grozio A, Kubota S, Sasaki Y, Redpath P, Migaud ME, Apte RS, Uchida K, Yoshino J, Imai SI. Long-Term Administration of Nicotinamide Mononucleotide Mitigates Age-Associated Physiological Decline in Mice. Cell Metab. 2016 Dec 13;24(6):795-806.

Nicotinamide (Vitamin B3)是维生素B3的酰胺衍生物，可以抑制SIRT1（IC₅₀：50-180μM）和SIRT2（IC₅₀：2μM）的活性。Nicotinamide还可增加细胞中NAD⁺、ATP、ROS水平^[3]。

Nicotinamide (5mM ,72h) 处理衰老成纤维细胞可降低 ROS 水平，减少衰老成纤维细胞中衰老表型的出现^[1]。Nicotinamide (50-200μM) 处理 HepG2 细胞可剂量依赖性地增强 NAD⁺ 生物合成^[4]。

Nicotinamide（0.5/1.0 mg/kg）治疗可改变全身生理和体内代谢，而不会影响最大寿命^[2]。长期服用Nicotinamide（300 mg/kg/day；6 至 12 个月）可逆转外周组织中与年龄相关的基因表达变化，并增强骨骼肌的线粒体呼吸能力^[5]。