Tetramethyl Nordihydroguaiaretic acid (TMNDGA) is a synthetic derivative of NDGA (Nordihydroguaiaretic acid), a non-selective lipoxygenase inhibitor. TMNDGA showed the strongest anti-HIV activity.

In vitro: In Vero cells, TMNDGA inhibited Sp1 transcription factor binding at the HIV long terminal repeat promoter and at the α-ICP4 promoter with IC50 values of 11 and 43.5 μM, respectively. The IC50 of TMNDGA varied between 11.7 and 4 μM in 10 passages of HSV-1 and 4 passages of HSV-2 [2]. TMNDGA inhibited Sp1-dependent Cdc2 gene expression. In M4N-treated transformed C3 cells, TMNDGA induced growth arrest and apoptosis by suppressing Sp1-dependent Cdc2 and survivin gene expression giving rise to its antitumorigenic activity [3]. TMNDGA treatment suppressed expression of the Sp1-dependent survivin gene. In transiently and stably survivin-transfected C3 cells, TMNDGA reduced caspase-3 activation by 50% and 75%, respectively [3]. TMNDGA inhibited the growth of a number of tumor cell lines by inducing apoptosis in a non-schedule-dependent manner [4]. TMNDGA inhibited the synthesis of DNA by melanoma cells and causes cell cycle arrest in G0/G1 and G2/M phases of the cell cycle [4].

In vivo: TMNDGA effectively inhibited the growth of human tumors in nude mice [5]. TMNDGA inhibited the growth of both murine and human melanomas and human colon cancer without apparent hepatic or renal toxicity [4]. In nude (nu/nu) mice bearing xenografts of human tumor types (Hep 3B, LNCaP, HT-29, MCF7, and K-562), treatment with TMNDGA (i.v. or i.p.) down-regulated Cdc2 and survivin genes expression [5].

References:
[1] Hwu J R, Tseng W N, Gnabre J, et al.  Antiviral activities of methylated nordihydroguaiaretic acids. 1. Synthesis, structure identification, and inhibition of tat-regulated HIV transactivation[J]. Journal of medicinal chemistry, 1998, 41(16): 2994-3000.
[2] Chen H, Teng L, Li J N, et al.  Antiviral activities of methylated nordihydroguaiaretic acids. 2. Targeting herpes simplex virus replication by the mutation insensitive transcription inhibitor tetra-O-methyl-NDGA[J]. Journal of medicinal chemistry, 1998, 41(16): 3001-3007.
[3] Chang C C, Heller J D, Kuo J, et al.  Tetra-O-methyl nordihydroguaiaretic acid induces growth arrest and cellular apoptosis by inhibiting Cdc2 and survivin expression[J]. Proceedings of the National Academy of Sciences of the United States of America, 2004, 101(36): 13239-13244.
[4] Lambert J D, Meyers R O, Timmermann B N, et al.  Tetra-O-methylnordihydroguaiaretic acid inhibits melanoma in vivo[J]. Cancer letters, 2001, 171(1): 47-56.
[5] Park R, Chang C C, Liang Y C, et al.  Systemic treatment with tetra-O-methyl nordihydroguaiaretic acid suppresses the growth of human xenograft tumors[J]. Clinical Cancer Research, 2005, 11(12): 4601-4609.