Hibiscus Tea for Blood Glucose Control and Hypertension

As I am without medical care, I recently started taking hibiscus tea (called "sour tea" in many countries) for my blood pressure (it acts somewhat like an ACE inhibitor, I gather). I noticed that around the same time, my blood sugar levels - fasting and post-prandial - dropped a bit. Does anyone know anything about this from anecdotal or, better yet, personal experience? It might be coincidence, but I did read a bit here and there on the web that suggested this action exists. (See links below)

Also, can anyone find anything with nutritional information about hibiscus tea? All I found was that the USDA nutrient database has a page on it that doesn't specify the amount of tea used, just the brewed quantity. If I'm going to be taking it a while, I want to know how much of various nutrients I'm getting, especially since there's ascorbic acid in that thar stuff and Dr. Bernstein reports that people supplementing with lots of vitamin C can both raise glucose and skew the glucose readings, themselves.

Info about the herb is here:
http://www.bu.edu/bhlp/Clinical/cross-cultural/herbal_index/herbs/Hibiscus%20Rosa%20Sinensis.html

http://uq.academia.edu/FarhadFatehi/Papers/406357/Effects_of_Sour_Tea_Hibiscus_Sabdariffa_on_Lipid_Profile_and_Lipoproteins_In_Patients_With_Type_II_Diabetes

http://mason.gmu.edu/~gkarman/projects/plant/plant.htm

Anyone? I'd really love to find out if anyone else is taking this tea or knows more about it.