Proof-of-Concept Randomized Controlled Study of Cognition Effects of the Proprietary Extract Sceletium tortuosum (Zembrin) Targeting Phosphodiesterase-4 in Cognitively Healthy Subjects: Implications for Alzheimer’s Dementia

Table 1

Cognitive outcome measures of Zembrin effects on neurobattery tests after 3 weeks of Zembrin treatment and placebo treatment.

Outcome measure	Mean score and SEM at baseline and after Zembrin and after placebo treatment
CNS Vital Signs; Key domains:	Baseline	After 3 weeks Zembrin		After 3 weeks of placebo		values	values
		()	[% change]	()	[% change]
Neurocognitive index (NCI)	36.3 (4.5)	43.9 (6.8)	[7.6]	47.2 (7.7)	[10.9]
Composite memory	38.9 (5.3)	32.9 (8.5)	[−6.0]	41.0 (9.0)	[2.1]
Verbal memory	36.9 (5.1)	41.6 (7.7)	[4.7]	43.7 (8.9)	[6.8]
Visual memory	45.6 (5.5)	29.5 (8.6)	[−16.1]	39.6 (7.2)	[−6.0]
Processing speed	56.7 (5.7)	77.4 (6.8)	[20.7]	54.7 (8.8)	[−2.0]
Executive function	36.8 (5.4)	60.8 (6.6)	[24.0]	50.1 (7.7)	[13.3]
Psychomotor speed	54.8 (5.6)	60.4 (8.2)	[5.6]	52.4 (8.5)	[−2.4]
Reaction time	45.8 (5.1)	58.1 (6.3)	[12.3]	59.1 (6.8)	[13.3]
Complex attention	38.5 (5.3)	46.2 (7.8)	[7.7]	44.9 (8.5)	[6.4]
Cognitive flexibility	35.4 (5.3)	60.2 (6.5)	[24.8]	49.7 (7.5)	[14.3]

Statistically different at two-tailed.