## 4 Biological Activity of Cannabis Metabolites
### Biological Activity of Cannabis Stilbenes
#### 4.4.1 In Vitro Activity of Cannabis Stilbenes  
Denbinobin possesses antiproliferative activity against A549 cells (lung adenocarcinoma) treated with 10 and 20 uM for 24 h (48.4% and 56.1% decrease in cell viability), due to apoptosis by Akt inactivation and Bad phosphorylation [113]. Denbinobin also exhibited significant antiproliferative activity against HT-29 and HCT-116 (colon cancer) cell lines at 10 uM [114]. Denbinobin demonstrated pro-oxidant and pro-apoptotic activity against human leukemic cell lines by inactivating the NF-kB pathway, and anti-HIV activity by inhibiting PMA- (IC\({}_{50}\) = 1.5 uM), TCR/CD28 binding- (IC\({}_{50}\) = 2.5 uM), and TNF-\(\alpha\)-induced (IC\({}_{50}\) =\(<\) 1 uM) LTR transcriptional activity [115]. Denbinobin's antiproliferative activity was tested against SK-Hep-1 (hepato carcinoma), SNU-484 (gastric cancer), and HeLa (cervical cancer), and it possesses an IC\({}_{50}\) of 16.4, 7.9, and 22.3 uM, respectively [116]. Moreover, 1-20 uM of denbinobin significantly reduced the invasiveness of SNU-484 cells in a dose-dependent manner (more than 40% reduction at 1 uM). HSC-T6 (rat liver stellate cells) treated with denbinobin (10, 30, and 50 uM) showed significant reduction in cell proliferation in a dose- and time-dependent manner [117]. Denbinobin is effective against the proliferation of two human glioblastoma cell lines (GBM8401 and U87 MG), in a dose-dependent fashion at 1-3 uM, via the downregulation of the IKK\(\alpha\)-Akt-FKHR signaling pathway [118]. [PERSON] et al. (2014) tested whether denbinobin can be helpful in preventing prostate cancer migration using PC3 cells. They recorded an IC\({}_{50}\) = 7.5 uM for 24 h denbinobin treatment, with a diminution of 80% in cell viability at 10 uM [119]. Additionally, denbinobin reduced PC3 cell migration at the tested concentrations (5 and 10 uM) by inhibiting CXCL12, which in turn activates Rac1, contributing to lamellipodia formation, which is necessary in metastasis, suggesting that denbinobin could be useful in treating prostate cancer and preventing metastasis. Denbinobin also presents potent anti-inflammatoryactivity, where it reduces iNOS and COX-2 expression and levels in RAW264.7 cells at 3 \(\upmu\)M [120]. Conjointly, denbinobin suppressed NF-\(\upkappa\)B activation and lowered TNF-\(\upalpha\), IL-10, and IL-1B mRNA expression. Canniprene, a dihydrotisolbene unique to _Cannabis_ as of yet, has anti-inflammatory activity that results in a potent and dose-dependent inhibition of liposomease 5, even more so than cannflavin A, the most potent of the cannflavins for anti-inflammatory activity, with an IC\({}_{50}\) of 0.4 \(\upmu\)M [57; 60]. Cannabisiprenone had a much lower IC\({}_{50}\) of 9.3 \(\upmu\)M against lipoxygenase 5 [57]. Canniprene, like cannflavin A, has a dose-dependent inhibitory activity for microsomal prostaglandinE2 synthesis, but less than cannflavin A this time, with an IC\({}_{50}\) of 10 \(\upmu\)M [57]. Canniprene also exhibits antiproliferative activity on four of the human cell lines tested, namely MCF-7 (breast cancer), A549 (lung cancer), HepG2 (liver carcinoma), and HT-29 (colorectal adenocarcinoma), with nearly 90% or more dead cells for the four cell lines, with the weakest effect being observed against A549 at concentrations between 1 and 5 mg/L [18]. Three stilbenes first identified in 2018 by [PERSON] et al., namely \(\upalpha\),\(\upalpha^{\prime}\)-dihydro-3\({}^{\prime}\),4\({}^{\prime}\)-trihydroxy-4\({}^{\prime}\)-methoxy-3-isopentenylsttilbene (HM1), \(\upalpha\),\(\upalpha^{\prime}\)-dihydro-3\({}^{\prime}\),4\({}^{\prime}\)-5-trihydroxy-4-methoxy-2,6-diisopentenylsttilbene (HM2), and \(\upalpha\),\(\upalpha^{\prime}\)-dihydro-3\({}^{\prime}\),4\({}^{\prime}\)-trihydroxy-4\({}^{\prime}\)-methoxy-2\({}^{\prime}\),3-diisopentenylsttilbene (HM3) (Figure 16), demonstrate slight cytotoxic activities against MCF-7 (breast cancer) and A549 (lung cancer) cell lines, whilst HM1 exhibits strong cytotoxic activity against those cell lines.