Lots of good recommendations. Generally, natural ways to lower P/B include...
CoQ10
Garlic
Hawthorn
Fish oil or Flax seed
Folic Acid
Vitamin C
Calcium, Magnesium, Potassium
Coleus forskohlii
Mistletoe
Rauwolfia
Diet - i.e. "DASH" particularly lower sodium *Diet is a MAJOR factor
Aerobic exercise
Meditation, yoga, and other mind/body relaxation and stress reducing methods